		bits	16
		cpu	8086
		;;; MS-DOS PSP locations
arglen:		equ	80h
argstart:	equ	82h
		;;; MS-DOS system calls
getch:		equ	1h
putch:		equ	2h
puts:		equ	9h
time:		equ	2Ch
section		.text
		org	100h
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Read board size from command line
		cmp	byte [arglen],0	; Command line empty?
		je	printusage	; Then print usage and stop
		mov	al,[argstart]	; Get first byte on command line
		cmp	al,'3'		; <3?
		jb	printusage	; Then print usage and stop
		cmp	al,'8'		; >8?
		ja	printusage	; Then print usage and stop
		sub	al,'0'		; Make number from ASCII
		mov	[boardsz],al	; Store the board size
		mov	ah,puts		; If we made it here, print the
		mov	dx,welcome	; welcome banner.
		int	21h
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Generate random board
		call	xabcinit	; Initialize the RNG with system time
		mov	si,board
		xor	bx,bx
genboard:	call 	xabcrand	; Get random byte
		mov	ah,al
		call	xabcrand	; Get another
		and	ax,0101h	; Keep only the low bit of each byte
		mov	[si+bx],ax	; And store them
		inc	bx		; Two bytes onward
		inc	bx
		cmp 	bl,64		; Are we done?
		jne	genboard
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Copy the board into the goal
		mov	si,board	; Source is board
		mov	di,goal		; Destination is goal
		mov	bx,0		; Start at the beginning
copyboard:	mov	ax,[si+bx]	; Load word from board
		mov	[di+bx],ax	; Store word in goal
		inc	bx		; We've copied two bytes
		inc	bx
		cmp 	bl,64		; Are we done yet?
		jne 	copyboard
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Make an amount of random flips
		call	xabcrand	; Random number
		and	al,15		; [0..15]
		add	al,5		; [5..20]
		mov	[sysflips],al	; Store in memory
		mov	cl,al		; Flip doesn't touch CL
		xor	ch,ch		; Set high byte zero
randflips:	call	xabcrand	; Random number
		call 	flip		; Do a flip (unused bits are ignored)
		loop 	randflips
		mov	byte [usrflips],0	; Initialize user flips to 0
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Print game status (moves, goal moves)
status:		mov	ah,puts
		mov	dx,smoves
		int	21h
		mov	al,[usrflips]
		call	printal
		mov	ah,puts
		mov	dx,sgoal
		int	21h
		mov	al,[sysflips]
		call	printal
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Print the game board and goal board
		mov	ah,puts		; Print the header
		mov	dx,sboardhdr
		int	21h
		mov	cl,2		; Print two headers
		mov	ah,putch	; Indent columns
		;;; Print column headers
colheader:	mov	dl,' '
		int	21h
		int	21h
		mov	bh,0		; Offset
		mov	bl,'A'		; First letter
.curcol:	cmp 	bh,[boardsz]
		mov	dl,bl		; Print letter
		jb	.printcol
		mov	dl,' '		; Print space if column not used
.printcol:	call	dlspace		; Print DL + separator space
		inc	bl
		inc	bh
		cmp 	bh,8		; Done yet?
		jb	.curcol
		mov	dl,9		; Separate the boards with a TAB
		int	21h
		dec	cl		; We need two headers (board and goal)
		jnz	colheader
		mov	ah,puts		; Print a newline afterwards
		mov	dx,newline
		int	21h
		;;; Print the rows of the boards
		xor	bh,bh		; Zero high byte of BX
		xor	cl,cl		; Row index
boardrow:	mov	ch,2		; Two rows, board and goal
		mov	si,board	; Start by printing the game board
.oneboard:	xor	dh,dh		; Column index
		mov	dl,cl		; Print row number
		add	dl,'1'
		call	dlspace
.curpos:	cmp	dh,[boardsz]	; Column in use?
		mov	dl,' '		; If not, print a space
		jae	.printpos
		mov	bl,cl		; Row index
		shl	bl,1		; * 8
		shl 	bl,1
		shl 	bl,1
		add	bl,dh		; Add column index
		mov	dl,[bx+si]	; Get position from board
		add	dl,'0'		; Print as ASCII 0 or 1
.printpos:	call	dlspace
		inc	dh		; Increment column index
		cmp	dh,8		; Are we there yet?
		jb	.curpos		; If not, print next position
		mov	dl,9		; Separate the boards with a TAB
		int	21h
		dec	ch		; Have we printed the goal yet?
		mov	si,goal		; If not, print the goal next
		jnz	.oneboard
		mov	ah,puts		; Print a newline
		mov	dx,newline
		int	21h
		inc	cl		; Next row
		cmp	cl,[boardsz]	; Are we there yet?
		jb	boardrow	; If not, print the next row.
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Ask the user for a move
		mov	ah,puts		; Write the prompt
		mov	dx,prompt
		int	21h
readmove:	mov	ah,getch 	; Read a character
		int	21h
		or	al,32		; Make letters lowercase
		cmp 	al,'q'		; Quit?
		je	quit
		cmp	al,'9'		; Numeric (row) input?
		jbe	.nummove	; If not, alphabetic (column) input
		;;; Letter input (column)
		sub	al,'a'		; Subtract 'a'
		jc	invalid		; If it was <'a', invalid input
		cmp 	al,[boardsz]	; Is it on the board?
		jae	invalid
		or	al,128		; Set high bit, for column flip
		call	flip		; Flip the column
		jmp	checkwin	; See if the user has won
		;;; Number input (row)
.nummove:	sub	al,'1'		; Rows start at 1.
		jc	invalid		; If <'1', then invalid
		cmp	al,[boardsz]	; Is it on the board?
		jae	invalid
		call	flip		; Flip the row
		;;; Check if the user has won the game
checkwin:	xor	bh,bh		; Zero high byte of array index
		mov	dl,[boardsz]
		xor	ch,ch		; Row coordinate
.row:		xor	cl,cl		; Column coordinate
.pos:		mov	bl,ch		; BL = row*8 + col
		shl	bl,1
		shl	bl,1
		shl 	bl,1
		add	bl,cl
		mov 	al,[board+bx]	; Get position from board
		cmp	al,[goal+bx]	; Compare with corresponding goal pos
		jne	.nowin		; Not equal: the user hasn't won
		inc	cl
		cmp	cl,dl		; Done all positions on row?
		jb	.pos		; If not, do next.
		inc	ch
		cmp	ch,dl 		; Done all rows?
		jb	.row		; If not, do next.
		;;; If we get here, the user has won
		mov	ah,puts
		mov	dx,win
		int	21h
		ret
		;;; The user hasn't won
.nowin:		inc	byte [usrflips]	; Record that the user has made a move
		jmp	status		; Print status and board, get new move
		;;; Invalid input
invalid:	mov	ah,puts
		mov	dx,nope
		int	21h
		jmp	readmove
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Flip the line or column in AL. If bit 7 set, flip column.
flip:		mov	si,board	; SI = board
		test	al,al		; This sets sign flag if bit 7 set
		js	.column		; If so, flip column.
		and	al,7		; We only need the first 3 bits
		shl	al,1		; Multiply by 8
		shl	al,1		; 8086 does not support 'shl al,3'
		shl 	al,1
		xor	ah,ah 		; High byte 0
		mov	bx,ax		; BX = offset
		mov	ah,4		; 4 words
.rowloop	xor	word [si+bx],0101h	; Flip two bytes at once
		inc	bx
		inc	bx
		dec	ah
		jnz	.rowloop
		ret
.column:	and	al,7		; Flip a column.
		xor	ah,ah
		mov	bx,ax		; BX = row offset
		mov	ah,8		; 8 bytes (need to do it byte by byte)
.colloop:	xor	byte [si+bx],01h	; Flip position
		add	bx,8
		dec	ah
		jnz	.colloop
quit:		ret
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Print usage and stop
printusage:	mov	ah,puts
		mov	dx,usage
		int	21h
		ret
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Print the character in DL followed by a space
dlspace:	mov	ah,putch
		int	21h
		mov	dl,' '
		int	21h
		ret
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Initialize the random number generator using the system
		;;; time.
xabcinit:	mov	ah,time
		int	21h
		mov	bx,xabcdat
		xor	[bx],cx
		xor	[bx+2],dx
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; The "X ABC" random number generator
		;;; Return random byte in AL
xabcrand:	push	bx		; Save registers
		push	cx
		push	dx
		mov	bx,xabcdat	; RNG state pointer
		mov	cx,[bx]		; CL=x CH=a
		mov	dx,[bx+2]	; DL=b DH=c
		inc 	cl		; X++
		xor	ch,dh		; A^=C
		xor	ch,cl		; A^=X
		add	dl,ch		; B+=A
		mov	al,dl
		shr	al,1		; B>>1
		xor	al,ch		; ^A
		add	al,dh		; +C
		mov	dh,al		; ->C
		mov	[bx],cx		; Store new RNG state
		mov	[bx+2],dx
		pop	dx		; Restore registers
		pop 	cx
		pop 	bx
		ret
		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		;;; Print the byte in AL as a decimal number
printal:	mov	di,decnum + 3	; Room in memory for decimal number
		mov	dl,10		; Divide by 10
.loop:		xor	ah,ah		; Zero remainder
		div	dl		; Divide by 10
		add	ah,'0'		; Add ASCII 0 to remainder
		dec	di
		mov	[di],ah		; Store digit in memory
		and	al,al		; Done yet?
		jnz	.loop		; If not, next digit
		mov	dx,di		; DX = number string
		mov	ah,puts		; Print the string
		int	21h
		ret
section		.data
decnum:		db	'***$'	; Decimal number placeholder
usage:		db	'Usage: FLIP [3..8], number is board size.$'
welcome:	db	'*** FLIP THE BITS *** ',13,10
		db	'--------------------- ',
newline:	db	13,10,'$'
smoves:		db	13,10,13,10,'Your flips: $'
sgoal:		db	9,'Goal: $'
sboardhdr:	db	13,10,10,'--Board------------'
		db	9,'--Goal-------------',13,10,'$'
prompt:		db	13,10,'Press line or column to flip, or Q to quit: $'
nope:		db	8,32,8,7,'$'	; Beep and erase input
win:		db	13,10,7,7,7,'You win!$'
section		.bss
boardsz:	resb 	1	; Board size
sysflips:	resb	1	; Amount of flips that the system does
usrflips:	resb	1	; Amount of flips that the user does
xabcdat:	resb	4	; Four byte RNG state
board:		resb	64	; 8*8 board
goal:		resb	64	; 8*8 goal


BYTE boardX=[13],boardY=[10],goalX=[22]

PROC UpdateBoard(BYTE ARRAY board BYTE side,x0,y0)
  BYTE x,y

  FOR y=0 TO side-1
  DO
    Position(x0,y0+2+y)
    Put(y+'1)
    FOR x=0 TO side-1
    DO
      IF y=0 THEN
        Position(x0+2+x,y0)
        Put(x+'A)
      FI
      Position(x0+2+x,y0+2+y)
      PrintB(board(x+y*side))
    OD
  OD
RETURN

PROC Randomize(BYTE ARRAY board BYTE len)
  BYTE i

  FOR i=0 TO len-1
  DO
    board(i)=Rand(2)
  OD
RETURN

BYTE FUNC Solved(BYTE ARRAY goal,board BYTE side)
  BYTE i,len

  len=side*side
  FOR i=0 TO len-1
  DO
    IF goal(i)#board(i) THEN
      RETURN (0)
    FI
  OD
RETURN (1)

PROC FlipRow(BYTE ARRAY board BYTE side,row)
  BYTE i,ind

  IF row>=side THEN RETURN FI
  FOR i=0 TO side-1
  DO
    ind=i+row*side
    board(ind)=1-board(ind)
  OD
  UpdateBoard(board,side,boardX,boardY)
RETURN

PROC FlipColumn(BYTE ARRAY board BYTE side,column)
  BYTE i,ind

  IF column>=side THEN RETURN FI
  FOR i=0 TO side-1
  DO
    ind=column+i*side
    board(ind)=1-board(ind)
  OD
  UpdateBoard(board,side,boardX,boardY)
RETURN

PROC Wait(BYTE frames)
  BYTE RTCLOK=$14
  frames==+RTCLOK
  WHILE frames#RTCLOK DO OD
RETURN

PROC UpdateStatus(BYTE ARRAY goal,board BYTE side)
  Position(9,3) Print("Game status: ")
  IF Solved(goal,board,side) THEN
    Print("SOLVED !")
    Sound(0,100,10,5) Wait(5)
    Sound(0,60,10,5) Wait(5)
    Sound(0,40,10,5) Wait(5)
    Sound(0,0,0,0)
  ELSE
    Print("Shuffled")
  FI
RETURN

PROC Init(BYTE ARRAY goal,board BYTE side)
  BYTE size,i,n

  size=side*side
  Randomize(goal,size)
  MoveBlock(board,goal,size)
  UpdateBoard(goal,side,goalX,boardY)

  WHILE Solved(goal,board,side)
  DO
    FOR i=1 TO 20
    DO
      n=Rand(side)
      IF Rand(2)=0 THEN
        FlipRow(board,side,n)
      ELSE
        FlipColumn(board,side,n)
      FI
    OD
  OD
RETURN

PROC Main()
  DEFINE SIDE="3"
  DEFINE SIZE="9"
  BYTE ARRAY board(SIZE),goal(SIZE)
  BYTE CRSINH=$02F0 ;Controls visibility of cursor
  BYTE k,CH=$02FC ;Internal hardware value for last key pressed

  Graphics(0)
  SetColor(2,0,2)
  CRSINH=1 ;hide cursor
  Position(boardX,boardY-2) Print("Board")
  Position(goalX+1,boardY-2) Print("Goal")
  Position(9,19) Print("Space bar - shuffle")
  Init(goal,board,SIDE)
  UpdateStatus(goal,board,side)

  DO
    k=CH
    IF k#$FF THEN
      CH=$FF
      IF k=31 THEN FlipRow(board,SIDE,0)
      ELSEIF k=30 THEN FlipRow(board,SIDE,1)
      ELSEIF k=26 THEN FlipRow(board,SIDE,2)
      ELSEIF k=63 THEN FlipColumn(board,SIDE,0)
      ELSEIF k=21 THEN FlipColumn(board,SIDE,1)
      ELSEIF k=18 THEN FlipColumn(board,SIDE,2)
      ELSEIF k=33 THEN Init(goal,board,SIDE) FI

      UpdateStatus(goal,board,SIDE)
    FI
  OD
RETURN


with Ada.Text_IO, Ada.Command_Line, Ada.Numerics.Discrete_Random;

procedure Flip_Bits is

   subtype Letter is Character range 'a' .. 'z';

   Last_Col: constant letter := Ada.Command_Line.Argument(1)(1);
   Last_Row: constant Positive := Positive'Value(Ada.Command_Line.Argument(2));

   package Boolean_Rand is new Ada.Numerics.Discrete_Random(Boolean);
   Gen: Boolean_Rand.Generator;

   type Matrix is array
     (Letter range 'a' .. Last_Col, Positive range 1 .. Last_Row) of Boolean;

   function Rand_Mat return Matrix is
      M: Matrix;
   begin
      for I in M'Range(1) loop
	 for J in M'Range(2) loop
	    M(I,J) := Boolean_Rand.Random(Gen);
	 end loop;
      end loop;
      return M;
   end Rand_Mat;

   function Rand_Mat(Start: Matrix) return Matrix is
      M: Matrix := Start;
   begin
      for I in M'Range(1) loop
	 if  Boolean_Rand.Random(Gen) then
	    for J in M'Range(2) loop
	       M(I,J) := not M(I, J);
	    end loop;
	 end if;
      end loop;
      for I in M'Range(2) loop
	 if  Boolean_Rand.Random(Gen) then
	    for J in M'Range(1) loop
	       M(J,I) := not M(J, I);
	    end loop;
	 end if;
      end loop;
      return M;
   end Rand_Mat;

   procedure Print(Message: String; Mat: Matrix) is
      package NIO is new Ada.Text_IO.Integer_IO(Natural);
   begin
      Ada.Text_IO.New_Line;
      Ada.Text_IO.Put_Line(Message);
      Ada.Text_IO.Put("   ");
      for Ch in Matrix'Range(1) loop
	 Ada.Text_IO.Put(" " & Ch);
      end loop;
      Ada.Text_IO.New_Line;
      for I in Matrix'Range(2) loop
	 NIO.Put(I, Width => 3);
	 for Ch in Matrix'Range(1) loop
	    Ada.Text_IO.Put(if Mat(Ch, I) then " 1" else " 0");
	 end loop;
         Ada.Text_IO.New_Line;
      end loop;
   end Print;

   Current, Target: Matrix;
   Moves: Natural := 0;

begin
   -- choose random Target and start ("Current") matrices
   Boolean_Rand.Reset(Gen);
   Target := Rand_Mat;
   loop
      Current := Rand_Mat(Target);
      exit when Current /= Target;
   end loop;
   Print("Target:", Target);

   -- print and modify Current matrix, until it is identical to Target
   while Current /= Target loop
     Moves := Moves + 1;
     Print("Current move #" & Natural'Image(Moves), Current);
      Ada.Text_IO.Put_Line("Flip row 1 .." & Positive'Image(Last_Row) &
			     " or column 'a' .. '" & Last_Col & "'");
      declare
	 S: String := Ada.Text_IO.Get_Line;
	 function Let(S: String) return Character is (S(S'First));
	 function Val(Str: String) return Positive is (Positive'Value(Str));
      begin
	 if Let(S) in 'a' .. Last_Col then
	    for I in Current'Range(2) loop
	       Current(Let(S), I) := not Current(Let(S), I);
	    end loop;
	 else
	    for I in Current'Range(1) loop
	       Current(I, Val(S)) := not Current(I, Val(S));
	    end loop;
	 end if;
      end;
   end loop;

   -- summarize the outcome
   Ada.Text_IO.Put_Line("Done after" & Natural'Image(Moves) & " Moves.");
end Flip_Bits;


#!/usr/local/bin/apl -s --

∇r←b FlipRow ix             ⍝ Flip a row
        r←b
        r[ix;]←~r[ix;]
∇

∇r←b FlipCol ix             ⍝ Flip a column
        r←b
        r[;ix]←~r[;ix]
∇

∇r←RandFlip b;ix            ⍝ Flip a random row or column
        ix←?↑⍴b
        →(2|?2)/col
        r←b FlipRow ix ⋄ →0
col:    r←b FlipCol ix
∇

∇s←ttl ShowBoard b;d        ⍝ Add row, column indices and title to board
        s←'-'⍪⍕(' ',⎕UCS 48+d),(⎕UCS 64+d←⍳↑⍴b)⍪b
        s←((2⊃⍴s)↑ttl)⍪s
∇

∇b←MkBoard n                ⍝ Generate random board
        b←(?(n,n)⍴2)-1
∇

∇Game;n;board;goal;moves;swaps;in;tgt
        ⍝⍝ Initialize
        ⎕RL←(2*32)|×/⎕TS    ⍝ random seed from time
        →(5≠⍴⎕ARG)/usage    ⍝ check argument
        →(~'0123456789'∧.∊⍨n←5⊃⎕ARG)/usage
        →((3>n)∨8<n←⍎n)/usage
        board←goal←MkBoard n    ⍝ Make a random board of the right size
        swaps←4+?16             ⍝ 5 to 20 swaps
        board←(RandFlip⍣swaps)board
        moves←0
        ⎕←'*** Flip the bits! ***'
        ⎕←'----------------------'

        ⍝⍝ Print game state
state:  ⎕←''
        ⎕←'Swaps:',moves,'   Goal:',swaps
        ⎕←''
        ('Board'ShowBoard board),' ',' ',' ',' ','Goal'ShowBoard goal

        ⍝⍝ Handle move
        ⍞←'Press line or column to flip, or Q to quit: '
read:   in←32⊤∨1⎕FIO[41]1
        →(in=⎕UCS'q')/0
        →((97≤in)∧(tgt←in-96)≤n)/col
        →((49≤in)∧(tgt←in-48)≤n)/row
        →read
col:    ⍞←⎕UCS in ⋄ board←board FlipCol tgt ⋄ →check
row:    ⍞←⎕UCS in ⋄ board←board FlipRow tgt

        ⍝⍝ Check if player won
check:  →(board≡goal)/win
        moves←moves+1
        →state
win:    ⎕←'You win!'
        →0
usage:  ⎕←'Usage:',⎕ARG[4],'[3..8]; number is board size.'
∇
Game
)OFF


size := 3 ; max 26
Gui, Add, Button, , O
Loop, %size%
{
	x := chr(A_Index+64)
	If x = A
		Loop, %size%
			Gui, Add, Button, y+4 gFlip, % A_Index
	Gui, Add, Button, ym gFlip, % x
	Loop, %size%
	{
		y := A_Index
		Random, %x%%y%, 0, 1
		Gui, Add, Edit, v%x%%y% ReadOnly, % %x%%y%
	}
}
Gui, Add, Text, ym, Moves:`nTarget:
Loop, %size%
{
	x := chr(A_Index+64)
	Loop, %size%
	{
		y := A_Index
		Gui, Add, Edit, % y=1 ? x="A" ? "xp+0 ym+30" : "x+14 ym+30" : "" . "ReadOnly vt" x y, % t%x%%y% := %x%%y%
	}
}Gui, Add, Text, xp-18 ym w30 Right vMoves, % Moves:=1

; randomize
While (i < size)
{
	Random, z, 1, %size%
	Random, x, 0, 1
	z := x ? chr(z+64) : z
	Solution .= z ; to cheat
	If Flip(z, size)
		i := 0 ; ensure we are not at the solution
	Else
		i++ ; count
}
Gui, Show, NA
Return

Flip(z, size) {
	Loop, %size%
	{
		If z is alpha
			GuiControl, , %z%%A_Index%, % %z%%A_Index% := !%z%%A_Index%
		Else
		{
			AIndex := chr(A_Index+64)
			GuiControl, , %AIndex%%z%, % %AIndex%%z% := !%AIndex%%z%
		}
	}
	Loop, %size%
	{
		x := chr(A_Index+64)
		Loop, %size%
		{
			y := A_Index
			If (%x%%y% != t%x%%y%)
				Return 0
		}
	}
	Return 1
}

Flip:
	GuiControl, , Moves, % Moves++
	If Flip(A_GuiControl, size)
	{
		Msgbox Success in %Moves% moves!
		Reload
	}
Return

ButtonO:
	Reload
Return

GuiEscape:
GuiClose:
	ExitApp
Return


10 DEFINT A-Z
20 PRINT "*** FLIP THE BITS ***"
30 INPUT "Board size";S
40 IF S<3 OR S>8 THEN PRINT "3 <= size <= 8": GOTO 30
50 RANDOMIZE
60 DIM B(S,S),G(S,S)
70 FOR X=1 TO S
80 FOR Y=1 TO S
90 B=INT(.5+RND(1))
100 B(X,Y)=B: G(X,Y)=B
110 NEXT Y,X
120 FOR A=0 TO 10+2*INT(10*RND(1))
130 R=INT(.5+RND(1))
140 N=1+INT(S*RND(1))
150 GOSUB 500
160 NEXT A: M=0
170 PRINT: M=M+1
180 PRINT " ==BOARD==";TAB(20);" ==GOAL=="
190 PRINT "   ";: GOSUB 400
200 PRINT TAB(20);"   ";: GOSUB 400
210 FOR N=1 TO S
220 FOR A=0 TO 1
230 PRINT TAB(A*20);CHR$(64+N);". ";
240 FOR C=1 TO S: IF A THEN B=G(C,N) ELSE B=B(C,N)
250 PRINT USING "# ";B;
260 NEXT C,A
270 PRINT
280 NEXT N
290 PRINT
300 LINE INPUT "Enter row or column: ";I$
310 IF LEN(I$)<>1 THEN 300 ELSE C=ASC(I$) OR 32
320 IF C<97 THEN N=C-48:R=0 ELSE N=C-96:R=1
330 IF N<1 OR N>S THEN 300 ELSE GOSUB 500
340 W=1=1
350 FOR X=1 TO S:FOR Y=1 TO S
360 W=W AND (B(X,Y)=G(X,Y))
370 NEXT Y,X
380 IF W THEN PRINT:PRINT "You win! Moves:";M:END
390 GOTO 170
400 FOR I=1 TO S: PRINT USING "# ";I;: NEXT I: RETURN
500 IF R THEN 510 ELSE 520
510 FOR I=1 TO S: B(I,N)=1-B(I,N): NEXT I: RETURN
520 FOR I=1 TO S: B(N,I)=1-B(N,I): NEXT I: RETURN


get "libhdr"
static $( randstate = ? $)

let rand() = valof
$(  randstate := random(randstate)
    resultis randstate >> 7
$)

let showboard(size, board, goal) be
$(  writes(" == BOARD == ")
    for i=1 to 19 do wrch(' ')
    writes(" == GOAL ==*N")

    for i=1 to 2
    $(  writes("  ")
        for j=1 to size do writef(" %N",j)
        test i=1 for j=1 to 30-2*size do wrch(' ') or wrch('*N')
    $)

    for row=0 to size-1 for i=1 to 2
    $(  writef("%C.", 'A'+row)
        for col=0 to size-1 do
            writef(" %N", (i=1->board,goal)!(row*size+col))
        test i=1 for j=1 to 30-2*size do wrch(' ') or wrch('*N')
    $)
$)

let readmove(size) = valof
$(  let ch = ? and x = ?
    writes("Enter row or column, or Q to quit: ")
    ch := rdch()
    unless ch = '*N' x := rdch() repeatuntil x = '*N'
    ch := ch | 32;
    if ch = 'q' | ch = endstreamch finish
    if 0 <= (ch-'1') < size | 0 <= (ch-'a') < size resultis ch
$) repeat

let flip(size, board, n, col) be
    test col
        do flipcol(size, board, n)
        or fliprow(size, board, n)
and flipcol(size, board, n) be
    for i=0 to size-1 do
        board!(i*size+n) := 1-board!(i*size+n)
and fliprow(size, board, n) be
    for i=0 to size-1 do
        board!(n*size+i) := 1-board!(n*size+i)

let makegoal(size, goal) be
    for i=0 to size*size-1 do goal!i := rand() & 1

let makeboard(size, board, goal) be
$(  for i=0 to size*size-1 do board!i := goal!i
    for i=0 to 10+2*(rand() & 15) do
        flip(size, board, rand() rem size, rand() & 1)
$)

let win(size, board, goal) = valof
$(  for i=0 to size*size-1
        unless board!i = goal!i resultis false
    resultis true
$)

let play(size, board, goal) be
$(  let moves = 0 and move = ?
    $(  showboard(size, board, goal)
        wrch('*N')
        if win(size, board, goal)
        $(  writef("You won in %N moves!*N", moves)
            return
        $)
        moves := moves + 1
        move := readmove(size)
        test '0' <= move <= '9'
            do flipcol(size, board, move-'1')
            or fliprow(size, board, move-'a')
    $) repeat
$)

let start() be
$(  let board = vec 63 and goal = vec 63
    let size = ?
    writef("****** FLIP THE BITS *******N")
    $(  writef("Size (3-8)? ")
        size := readn()
    $) repeatuntil 3 <= size <= 8
    writef("Random number seed? ")
    randstate := readn()
    wrch('*N')
    makegoal(size, goal)
    makeboard(size, board, goal)
    play(size, board, goal)
$)


#include <stdio.h>
#include <stdlib.h>

int i, j;

void fliprow(int **b, int sz, int n)
{
	for(i = 0; i < sz; i++)
		b[n+1][i] = !b[n+1][i];
}

void flipcol(int **b, int sz, int n)
{
	for(i = 1; i <= sz; i++)
		b[i][n] = !b[i][n];
}

void initt(int **t, int sz)
{
	for(i = 1; i <= sz; i++)
		for(j = 0; j < sz; j++)
			t[i][j] = rand()%2;
}

void initb(int **t, int **b, int sz)
{
	for(i = 1; i <= sz; i++)
		for(j = 0; j < sz; j++)
			b[i][j] = t[i][j];

	for(i = 1; i <= sz; i++)
		fliprow(b, sz, rand()%sz+1);
	for(i = 0; i < sz; i++)
		flipcol(b, sz, rand()%sz);
}

void printb(int **b, int sz)
{
	printf(" ");
	for(i = 0; i < sz; i++)
		printf(" %d", i);
	printf("\n");

	for(i = 1; i <= sz; i++)
	{
		printf("%d", i-1);
		for(j = 0; j < sz; j++)
			printf(" %d", b[i][j]);
		printf("\n");
	}

	printf("\n");
}

int eq(int **t, int **b, int sz)
{
	for(i = 1; i <= sz; i++)
		for(j = 0; j < sz; j++)
			if(b[i][j] != t[i][j])
				return 0;
	return 1;
}

void main()
{
	int sz = 3;
	int eql = 0;
	int mov = 0;
	int **t = malloc(sz*(sizeof(int)+1));
	for(i = 1; i <= sz; i++)
		t[i] = malloc(sz*sizeof(int));

	int **b = malloc(sz*(sizeof(int)+1));
	for(i = 1; i <= sz; i++)
		b[i] = malloc(sz*sizeof(int));
	char roc;
	int n;
	initt(t, sz);
	initb(t, b, sz);

	while(eq(t, b, sz))
		initb(t, b, sz);

	while(!eql)
	{
		printf("Target: \n");
		printb(t, sz);
		printf("Board: \n");
		printb(b, sz);
		printf("What to flip: ");
		scanf(" %c", &roc);
		scanf(" %d", &n);

		switch(roc)
		{
			case 'r':
				fliprow(b, sz, n);
				break;
			case 'c':
				flipcol(b, sz, n);
				break;
			default:
				perror("Please specify r or c and an number");
				break;
		}

		printf("Moves Taken: %d\n", ++mov);

		if(eq(t, b, sz))
		{
			printf("You win!\n");
			eql = 1;
		}
	}
}


#include <time.h>
#include <iostream>
#include <string>

typedef unsigned char byte;
using namespace std;

class flip
{
public:
    flip() { field = 0; target = 0; }
    void play( int w, int h ) { wid = w; hei = h; createField(); gameLoop(); }

private:
    void gameLoop()
    {
	int moves = 0;
	while( !solved() )
	{
	    display(); string r; cout << "Enter rows letters and/or column numbers: "; cin >> r;
	    for( string::iterator i = r.begin(); i != r.end(); i++ )
	    {
		byte ii = ( *i );
		if( ii - 1 >= '0' && ii - 1 <= '9' ) { flipCol( ii - '1' ); moves++; }
		else if( ii >= 'a' && ii <= 'z' ) { flipRow( ii - 'a' ); moves++; }
	    }
	}
	cout << endl << endl << "** Well done! **" << endl << "Used " << moves << " moves." << endl << endl;
    }

    void display()
    { system( "cls" ); output( "TARGET:", target ); output( "YOU:", field ); }

    void output( string t, byte* f )
    {
	cout << t << endl;
	cout << " "; for( int x = 0; x < wid; x++ ) cout << " " << static_cast<char>( x + '1' ); cout << endl;
	for( int y = 0; y < hei; y++ )
	{
	    cout << static_cast<char>( y + 'a' ) << " ";
	    for( int x = 0; x < wid; x++ )
		cout << static_cast<char>( f[x + y * wid] + 48 ) << " ";
	    cout << endl;
	}
	cout << endl << endl;
    }

    bool solved()
    {
	for( int y = 0; y < hei; y++ )
	    for( int x = 0; x < wid; x++ )
		if( target[x + y * wid] != field[x + y * wid] ) return false;
	return true;
    }

    void createTarget()
    {
	for( int y = 0; y < hei; y++ )
	    for( int x = 0; x < wid; x++ )
		if( frnd() < .5f ) target[x + y * wid] = 1;
	        else target[x + y * wid] = 0;
	memcpy( field, target, wid * hei );
    }

    void flipCol( int c )
    { for( int x = 0; x < hei; x++ ) field[c + x * wid] = !field[c + x * wid]; }

    void flipRow( int r )
    { for( int x = 0; x < wid; x++ ) field[x + r * wid] = !field[x + r * wid]; }

    void calcStartPos()
    {
	int flips = ( rand() % wid + wid + rand() % hei + hei ) >> 1;
	for( int x = 0; x < flips; x++ )
	{ if( frnd() < .5f ) flipCol( rand() % wid ); else flipRow( rand() % hei ); }
    }

    void createField()
    {
        if( field ){ delete [] field; delete [] target; }
        int t = wid * hei; field = new byte[t]; target = new byte[t];
	memset( field, 0, t ); memset( target, 0, t ); createTarget();
	while( true ) { calcStartPos(); if( !solved() ) break; }
    }

    float frnd() { return static_cast<float>( rand() ) / static_cast<float>( RAND_MAX ); }

    byte* field, *target; int wid, hei;
};

int main( int argc, char* argv[] )
{ srand( time( NULL ) ); flip g; g.play( 3, 3 ); return system( "pause" ); }


(defn cols [board]
  (mapv vec (apply map list board)))

(defn flipv [v]
  (mapv #(if (> % 0) 0 1) v))

(defn flip-row [board n]
  (assoc board n (flipv (get board n))))

(defn flip-col [board n]
  (cols (flip-row (cols board) n)))

(defn play-rand [board n]
  (if (= n 0)
    board
    (let [f (if (= (rand-int 2) 0) flip-row flip-col)]
      (recur (f board (rand-int (count board))) (dec n)))))

(defn rand-binary-vec [size]
  (vec (take size (repeatedly #(rand-int 2)))))

(defn rand-binary-board [size]
  (vec (take size (repeatedly #(rand-binary-vec size)))))

(defn numbers->letters [coll]
  (map #(char (+ 97 %)) coll))

(defn column-labels [size]
  (apply str (interpose " " (numbers->letters (range size)))))

(defn print-board [board]
  (let [size (count board)]
    (println "\t " (column-labels size))
    (dotimes [n size] (println (inc n) "\t" (board n)))))

(defn key->move [key]
  (let [start (int (first key))
        row-value (try (Long/valueOf key) (catch NumberFormatException e))]
    (cond
      (<= 97 start 122) [:col (- start 97)]
      (<= 65 start 90) [:col (- start 65)]
      (> row-value 0) [:row (dec row-value)]
      :else nil)))

(defn play-game [target-board current-board n]
  (println "\nTurn " n)
  (print-board current-board)
  (if (= target-board current-board)
    (println "You win!")
    (let [move (key->move (read-line))
          axis (first move)
          idx (second move)]
      (cond
        (= axis :row) (play-game target-board (flip-row current-board idx) (inc n))
        (= axis :col) (play-game target-board (flip-col current-board idx) (inc n))
        :else (println "Quitting!")))))

(defn -main
  "Flip the Bits Game!"
  [& args]
  (if-not (empty? args)
    (let [target-board (rand-binary-board (Long/valueOf (first args)))]
      (println "Target")
      (print-board target-board)
      (play-game target-board (play-rand target-board 3) 0))))


import std.stdio, std.random, std.ascii, std.string, std.range,
       std.algorithm, std.conv;

enum N = 3; // Board side.
static assert(N <= lowercase.length);
enum columnIDs = lowercase[0 .. N];
alias Board = ubyte[N][N];

void flipBits(ref Board board, in size_t count=1) {
    foreach (immutable _; 0 .. count)
        board[uniform(0, $)][uniform(0, $)] ^= 1;
}

void notRow(ref Board board, in size_t i) pure nothrow {
    board[i][] ^= 1;
}

void notColumn(ref Board board, in size_t i) pure nothrow {
    foreach (ref row; board)
        row[i] ^= 1;
}

Board generateGameBoard(in ref Board target) {
    // board is generated with many flips, to keep parity unchanged.
    Board board = target;
    while (board == target)
        foreach (immutable _; 0 .. 2 * N)
            [&notRow, &notColumn][uniform(0, 2)](board, uniform(0, N));
    return board;
}

void show(in ref Board board, in string comment) {
    comment.writeln;
    writefln("     %-(%c %)", columnIDs);
    foreach (immutable j, const row; board)
        writefln("  %2d %-(%d %)", j + 1, row);
}

void main() {
    "T prints the target, and Q exits.\n".writeln;
    // Create target and flip some of its bits randomly.
    Board target;
    flipBits(target, uniform(0, N) + 1);
    show(target, "Target configuration is:");

    auto board = generateGameBoard(target);
    immutable prompt = format("  1-%d / %s-%s to flip, or T, Q: ",
                              N, columnIDs[0], columnIDs.back);
    uint move = 1;
    while (board != target) {
        show(board, format("\nMove %d:", move));
        prompt.write;
        immutable ans = readln.strip;

        if (ans.length == 1 && columnIDs.canFind(ans)) {
            board.notColumn(columnIDs.countUntil(ans));
            move++;
        } else if (iota(1, N + 1).map!text.canFind(ans)) {
            board.notRow(ans.to!uint - 1);
            move++;
        } else if (ans == "T") {
            show(target, "Target configuration is:");
        } else if (ans == "Q") {
            return "Game stopped.".writeln;
        } else
            writefln("  Wrong input '%s'. Try again.\n", ans.take(9));
    }

    "\nWell done!".writeln;
}


defmodule Flip_game do
  @az  Enum.map(?a..?z, &List.to_string([&1]))
  @in2i Enum.concat(Enum.map(1..26, fn i -> {to_string(i), i} end),
                    Enum.with_index(@az) |> Enum.map(fn {c,i} -> {c,-i-1} end))
        |> Enum.into(Map.new)

  def play(n) when n>2 do
    target = generate_target(n)
    display(n, "Target: ", target)
    board = starting_config(n, target)
    play(n, target, board, 1)
  end

  def play(n, target, board, moves) do
    display(n, "Board: ", board)
    ans = IO.gets("row/column to flip: ") |> String.strip |> String.downcase
    new_board = case @in2i[ans] do
                  i when i in 1..n   -> flip_row(n, board, i)
                  i when i in -1..-n -> flip_column(n, board, -i)
                  _ -> IO.puts "invalid input: #{ans}"
                       board
                end
    if target == new_board do
      display(n, "Board: ", new_board)
      IO.puts "You solved the game in #{moves} moves"
    else
      IO.puts ""
      play(n, target, new_board, moves+1)
    end
  end

  defp generate_target(n) do
    for i <- 1..n, j <- 1..n, into: Map.new, do: {{i, j}, :rand.uniform(2)-1}
  end

  defp starting_config(n, target) do
    Enum.concat(1..n, -1..-n)
    |> Enum.take_random(n)
    |> Enum.reduce(target, fn x,acc ->
         if x>0, do: flip_row(n, acc, x),
               else: flip_column(n, acc, -x)
       end)
  end

  defp flip_row(n, board, row) do
    Enum.reduce(1..n, board, fn col,acc ->
      Map.update!(acc, {row,col}, fn bit -> 1 - bit end)
    end)
  end

  defp flip_column(n, board, col) do
    Enum.reduce(1..n, board, fn row,acc ->
      Map.update!(acc, {row,col}, fn bit -> 1 - bit end)
    end)
  end

  defp display(n, title, board) do
    IO.puts title
    IO.puts "   #{Enum.join(Enum.take(@az,n), " ")}"
    Enum.each(1..n, fn row ->
      :io.fwrite "~2w ", [row]
      IO.puts Enum.map_join(1..n, " ", fn col -> board[{row, col}] end)
    end)
  end
end

Flip_game.play(3)


!Implemented by Anant Dixit (October 2014)
program flipping_bits
implicit none
character(len=*), parameter :: cfmt = "(A3)", ifmt = "(I3)"
integer :: N, i, j, io, seed(8), moves, input
logical, allocatable :: Brd(:,:), Trgt(:,:)
logical :: solved
double precision :: r

do
  write(*,*) 'Enter the number of squares (between 1 and 10) you would like: '
  read(*,*,iostat=io) N
  if(N.gt.0 .and. N.le.10 .and. io.eq.0) exit
  write(*,*) 'Please, an integer between 1 and 10'
end do

allocate(Brd(N,N),Trgt(N,N))
call date_and_time(values=seed)
call srand(1000*seed(7)+seed(8)+60000*seed(6))
do i = 1,N
  do j = 1,N
    r = rand()
    if(r.gt.0.5D0) then
      Brd(i,j) = .TRUE.
      Trgt(i,j) = .TRUE.
    else
      Brd(i,j) = .FALSE.
      Trgt(i,j) = .FALSE.
    end if
  end do
end do
! Random moves taken by the program to `create' a target
moves = N
do i = 1,moves
  r = 1+2.0D0*dble(N)*rand() - 1.0D-17 !Only to make sure that the number is between 1 and 2N (less than 2N-1)
  if(floor(r).le.N) then
    do j = 1,N
      Trgt(floor(r),j) = .NOT.Trgt(floor(r),j)
    end do
  else
    r = r-N
    do j = 1,N
      Trgt(j,floor(r)) = .NOT.Trgt(j,floor(r))
    end do
  end if
end do

!This part checks if the target and the starting configurations are same or not.
do
  input = N
  call next_move(Brd,Trgt,N,input,solved)
  call next_move(Brd,Trgt,N,input,solved)
  if(solved) then
    r = 1+2.0D0*dble(N)*rand() - 1.0D-17
    if(floor(r).le.N) then
      do j = 1,N
        Trgt(floor(r),j) = .NOT.Trgt(floor(r),j)
      end do
    else
      r = r-N
      do j = 1,N
        Trgt(j,floor(r)) = .NOT.Trgt(j,floor(r))
      end do
    end if
  else
    exit
  end if
end do

write(*,*) 'Welcome to the Flipping Bits game!'
write(*,*) 'You have the current position'

moves = 0
call display(Brd,Trgt,N)
input = N
do
  write(*,*) 'Number of moves so far:', moves
  write(*,*) 'Select the column or row you wish to flip: '
  read(*,*,iostat=io) input
  if(io.eq.0 .and. input.gt.0 .and. input.le.(2*N)) then
    moves = moves+1
    write(*,*) 'Flipping ', input
    call next_move(Brd,Trgt,N,input,solved)
    call display(Brd,Trgt,N)
    if(solved) exit
  else
    write(*,*) 'Please enter a valid column or row number. To quit, press Ctrl+C!'
  end if
end do

write(*,*) 'Congratulations! You finished the game!'
write(*,ifmt,advance='no') moves
write(*,*) ' moves were taken by you!!'
deallocate(Brd,Trgt)
end program

subroutine display(Brd,Trgt,N)
implicit none
!arguments
integer :: N
logical :: Brd(N,N), Trgt(N,N)
!local
character(len=*), parameter :: cfmt = "(A3)", ifmt = "(I3)"
integer :: i, j
write(*,*) 'Current Configuration: '
do i = 0,N
  if(i.eq.0) then
    write(*,cfmt,advance='no') 'R/C'
    write(*,cfmt,advance='no') ' | '
  else
    write(*,ifmt,advance='no') i
  end if
end do
write(*,*)
do i = 0,N
  if(i.eq.0) then
    do j = 0,N+2
      write(*,cfmt,advance='no') '---'
    end do
  else
    write(*,ifmt,advance='no') i+N
    write(*,cfmt,advance='no') ' | '
    do j = 1,N
      if(Brd(i,j)) then
        write(*,ifmt,advance='no') 1
      else
        write(*,ifmt,advance='no') 0
      end if
    end do
  end if
  write(*,*)
end do

write(*,*)
write(*,*)

write(*,*) 'Target Configuration'
do i = 0,N
  if(i.eq.0) then
    write(*,cfmt,advance='no') 'R/C'
    write(*,cfmt,advance='no') ' | '
  else
    write(*,ifmt,advance='no') i
  end if
end do
write(*,*)
do i = 0,N
  if(i.eq.0) then
    do j = 0,N+2
      write(*,cfmt,advance='no') '---'
    end do
  else
    write(*,ifmt,advance='no') i+N
    write(*,cfmt,advance='no') ' | '
    do j = 1,N
      if(Trgt(i,j)) then
        write(*,ifmt,advance='no') 1
      else
        write(*,ifmt,advance='no') 0
      end if
    end do
  end if
  write(*,*)
end do
write(*,*)
write(*,*)
end subroutine

subroutine next_move(Brd,Trgt,N,input,solved)
implicit none
!arguments
integer :: N, input
logical :: Brd(N,N), Trgt(N,N), solved
!others
integer :: i,j

if(input.gt.N) then
  input = input-N
  do i = 1,N
    Brd(input,i) = .not.Brd(input,i)
  end do
else
  do i = 1,N
    Brd(i,input) = .not.Brd(i,input)
  end do
end if
solved = .TRUE.
do i = 1,N
  do j = 1,N
    if( (.not.Brd(i,j).and.Trgt(i,j)) .or. (Brd(i,j).and..not.Trgt(i,j)) ) then
      solved = .FALSE.
      exit
    end if
  end do
  if(.not.solved) exit
end do
end subroutine


package main

import (
	"fmt"
	"math/rand"
	"time"
)

func main() {

	rand.Seed(time.Now().UnixNano())

	var n int = 3 // Change to define board size
	var moves int = 0

	a := make([][]int, n)
	for i := range a {
		a[i] = make([]int, n)
		for j := range a {
			a[i][j] = rand.Intn(2)
		}
	}

    b := make([][]int, len(a))
	for i := range a {
		b[i] = make([]int, len(a[i]))
		copy(b[i], a[i])
	}

	for i := rand.Intn(100); i > 0 || compareSlices(a, b) == true; i-- {
		b = flipCol(b, rand.Intn(n) + 1)
		b = flipRow(b, rand.Intn(n) + 1)
	}

	fmt.Println("Target:")
	drawBoard(a)
	fmt.Println("\nBoard:")
	drawBoard(b)

	var rc rune
	var num int

	for {
		for{
			fmt.Printf("\nFlip row (r) or column (c)  1 .. %d (c1, ...): ", n)
			_, err := fmt.Scanf("%c%d", &rc, &num)
			if err != nil {
				fmt.Println(err)
				continue
			}
			if num < 1 || num > n {
				fmt.Println("Wrong command!")
				continue
			}
			break
		}

		switch rc {
			case 'c':
				fmt.Printf("Column %v will be flipped\n", num)
				flipCol(b, num)
			case 'r':
				fmt.Printf("Row %v will be flipped\n", num)
				flipRow(b, num)
			default:
				fmt.Println("Wrong command!")
				continue
		}

		moves++
		fmt.Println("\nMoves taken: ", moves)

		fmt.Println("Target:")
		drawBoard(a)
		fmt.Println("\nBoard:")
		drawBoard(b)

		if compareSlices(a, b) {
			fmt.Printf("Finished. You win with %d moves!\n", moves)
			break
		}
	}
}

func drawBoard (m [][]int) {
	fmt.Print("   ")
	for i := range m {
		fmt.Printf("%d ", i+1)
	}
	for i := range m {
		fmt.Println()
		fmt.Printf("%d ", i+1)
		for _, val := range m[i] {
			fmt.Printf(" %d", val)
		}
	}
	fmt.Print("\n")
}

func flipRow(m [][]int, row int) ([][]int) {
	for j := range m {
		m[row-1][j] ^= 1
	}
	return m
}

func flipCol(m [][]int, col int) ([][]int) {
	for j := range m {
		m[j][col-1] ^= 1
	}
	return m
}

func compareSlices(m [][]int, n[][]int) bool {
	o := true
	for i := range m {
		for j := range m {
			if m[i][j] != n[i][j] { o = false }
		}
	}
	return o
}


import Data.List (intersperse)

import System.Random (randomRIO)

import Data.Array (Array, (!), (//), array, bounds)

import Control.Monad (zipWithM_, replicateM, foldM, when)

type Board = Array (Char, Char) Int

flp :: Int -> Int
flp 0 = 1
flp 1 = 0

numRows, numCols :: Board -> String
numRows t =
  let ((a, _), (b, _)) = bounds t
  in [a .. b]

numCols t =
  let ((_, a), (_, b)) = bounds t
  in [a .. b]

flipRow, flipCol :: Board -> Char -> Board
flipRow t r =
  let e =
        [ (ix, flp (t ! ix))
        | ix <- zip (repeat r) (numCols t) ]
  in t // e

flipCol t c =
  let e =
        [ (ix, flp (t ! ix))
        | ix <- zip (numRows t) (repeat c) ]
  in t // e

printBoard :: Board -> IO ()
printBoard t = do
  let rows = numRows t
      cols = numCols t
      f 0 = '0'
      f 1 = '1'
      p r xs = putStrLn $ [r, ' '] ++ intersperse ' ' (map f xs)
  putStrLn $ "  " ++ intersperse ' ' cols
  zipWithM_
    p
    rows
    [ [ t ! (y, x)
      | x <- cols ]
    | y <- rows ]

-- create a random goal board, and flip rows and columns randomly
-- to get a starting board
setupGame :: Char -> Char -> IO (Board, Board)
setupGame sizey sizex
                -- random cell value at (row, col)
 = do
  let mk rc = (\v -> (rc, v)) <$> randomRIO (0, 1)
      rows = ['a' .. sizey]
      cols = ['1' .. sizex]
  goal <-
    array (('a', '1'), (sizey, sizex)) <$>
    mapM
      mk
      [ (r, c)
      | r <- rows
      , c <- cols ]
  start <-
    do let change :: Board -> Int -> IO Board
           -- flip random row
           change t 0 = flipRow t <$> randomRIO ('a', sizey)
           -- flip random col
           change t 1 = flipCol t <$> randomRIO ('1', sizex)
       numMoves <- randomRIO (3, 15) -- how many flips (3 - 15)
       -- determine if rows or cols are flipped
       moves <- replicateM numMoves $ randomRIO (0, 1)
       -- make changes and get a starting board
       foldM change goal moves
  if goal /= start -- check if boards are different
    then return (goal, start) -- all ok, return both boards
    else setupGame sizey sizex -- try again

main :: IO ()
main = do
  putStrLn "Select a board size (1 - 9).\nPress any other key to exit."
  sizec <- getChar
  when (sizec `elem` ['1' .. '9']) $
    do let size = read [sizec] - 1
       (g, s) <- setupGame (['a' ..] !! size) (['1' ..] !! size)
       turns g s 0
  where
    turns goal current moves = do
      putStrLn "\nGoal:"
      printBoard goal
      putStrLn "\nBoard:"
      printBoard current
      when (moves > 0) $
        putStrLn $ "\nYou've made " ++ show moves ++ " moves so far."
      putStrLn $
        "\nFlip a row (" ++
        numRows current ++ ") or a column (" ++ numCols current ++ ")"
      v <- getChar
      if v `elem` numRows current
        then check $ flipRow current v
        else if v `elem` numCols current
               then check $ flipCol current v
               else tryAgain
      where
        check t =
          if t == goal
            then putStrLn $ "\nYou've won in " ++ show (moves + 1) ++ " moves!"
            else turns goal t (moves + 1)
        tryAgain = do
          putStrLn ": Invalid row or column."
          turns goal current moves


start=:3 :0
  Moves=:0
  N=:i.y
  Board=: ?2$~,~y
  'fr fc'=. (2,y)$}.#:(+?&.<:@<:)2x^2*y
  End=: fr~:fc~:"1 Board
  Board;End
)

abc=:'abcdefghij'
move=:3 :0
  fc=. N e.abc i. y ([-.-.)abc
  fr=. N e._-.~_ "."0 abc-.~":y
  Board=: fr~:fc~:"1 Board
  smoutput (":Moves=:Moves++/fr,fc),' moves'
  if. Board-:End do.
    'yes'
  else.
    Board;End
  end.
)


import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class FlippingBitsGame extends JPanel {
    final int maxLevel = 7;
    final int minLevel = 3;

    private Random rand = new Random();
    private int[][] grid, target;
    private Rectangle box;
    private int n = maxLevel;
    private boolean solved = true;

    FlippingBitsGame() {
        setPreferredSize(new Dimension(640, 640));
        setBackground(Color.white);
        setFont(new Font("SansSerif", Font.PLAIN, 18));

        box = new Rectangle(120, 90, 400, 400);

        startNewGame();

        addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                if (solved) {
                    startNewGame();
                } else {
                    int x = e.getX();
                    int y = e.getY();

                    if (box.contains(x, y))
                        return;

                    if (x > box.x && x < box.x + box.width) {
                        flipCol((x - box.x) / (box.width / n));

                    } else if (y > box.y && y < box.y + box.height)
                        flipRow((y - box.y) / (box.height / n));

                    if (solved(grid, target))
                        solved = true;

                    printGrid(solved ? "Solved!" : "The board", grid);
                }
                repaint();
            }
        });
    }

    void startNewGame() {
        if (solved) {

            n = (n == maxLevel) ? minLevel : n + 1;

            grid = new int[n][n];
            target = new int[n][n];

            do {
                shuffle();

                for (int i = 0; i < n; i++)
                    target[i] = Arrays.copyOf(grid[i], n);

                shuffle();

            } while (solved(grid, target));

            solved = false;
            printGrid("The target", target);
            printGrid("The board", grid);
        }
    }

    void printGrid(String msg, int[][] g) {
        System.out.println(msg);
        for (int[] row : g)
            System.out.println(Arrays.toString(row));
        System.out.println();
    }

    boolean solved(int[][] a, int[][] b) {
        for (int i = 0; i < n; i++)
            if (!Arrays.equals(a[i], b[i]))
                return false;
        return true;
    }

    void shuffle() {
        for (int i = 0; i < n * n; i++) {
            if (rand.nextBoolean())
                flipRow(rand.nextInt(n));
            else
                flipCol(rand.nextInt(n));
        }
    }

    void flipRow(int r) {
        for (int c = 0; c < n; c++) {
            grid[r][c] ^= 1;
        }
    }

    void flipCol(int c) {
        for (int[] row : grid) {
            row[c] ^= 1;
        }
    }

    void drawGrid(Graphics2D g) {
        g.setColor(getForeground());

        if (solved)
            g.drawString("Solved! Click here to play again.", 180, 600);
        else
            g.drawString("Click next to a row or a column to flip.", 170, 600);

        int size = box.width / n;

        for (int r = 0; r < n; r++)
            for (int c = 0; c < n; c++) {
                g.setColor(grid[r][c] == 1 ? Color.blue : Color.orange);
                g.fillRect(box.x + c * size, box.y + r * size, size, size);
                g.setColor(getBackground());
                g.drawRect(box.x + c * size, box.y + r * size, size, size);
                g.setColor(target[r][c] == 1 ? Color.blue : Color.orange);
                g.fillRect(7 + box.x + c * size, 7 + box.y + r * size, 10, 10);
            }
    }

    @Override
    public void paintComponent(Graphics gg) {
        super.paintComponent(gg);
        Graphics2D g = (Graphics2D) gg;
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);

        drawGrid(g);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            JFrame f = new JFrame();
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            f.setTitle("Flipping Bits Game");
            f.setResizable(false);
            f.add(new FlippingBitsGame(), BorderLayout.CENTER);
            f.pack();
            f.setLocationRelativeTo(null);
            f.setVisible(true);
        });
    }
}


function numOfRows(board) { return board.length; }
function numOfCols(board) { return board[0].length; }
function boardToString(board) {
    // First the top-header
    var header = '   ';
    for (var c = 0; c < numOfCols(board); c++)
        header += c + ' ';

    // Then the side-header + board
    var sideboard = [];
    for (var r = 0; r < numOfRows(board); r++) {
        sideboard.push(r + ' [' + board[r].join(' ') + ']');
    }

    return header + '\n' + sideboard.join('\n');
}
function flipRow(board, row) {
    for (var c = 0; c < numOfCols(board); c++) {
        board[row][c] = 1 - board[row][c];
    }
}
function flipCol(board, col) {
    for (var r = 0; r < numOfRows(board); r++) {
        board[r][col] = 1 - board[r][col];
    }
}

function playFlippingBitsGame(rows, cols) {
    rows = rows | 3;
    cols = cols | 3;
    var targetBoard = [];
    var manipulatedBoard = [];
    // Randomly generate two identical boards.
    for (var r = 0; r < rows; r++) {
        targetBoard.push([]);
        manipulatedBoard.push([]);
        for (var c = 0; c < cols; c++) {
            targetBoard[r].push(Math.floor(Math.random() * 2));
            manipulatedBoard[r].push(targetBoard[r][c]);
        }
    }
    // Naive-scramble one of the boards.
    while (boardToString(targetBoard) == boardToString(manipulatedBoard)) {
        var scrambles = rows * cols;
        while (scrambles-- > 0) {
            if (0 == Math.floor(Math.random() * 2)) {
                flipRow(manipulatedBoard, Math.floor(Math.random() * rows));
            }
            else {
                flipCol(manipulatedBoard, Math.floor(Math.random() * cols));
            }
        }
    }
    // Get the user to solve.
    alert(
        'Try to match both boards.\n' +
        'Enter `r<num>` or `c<num>` to manipulate a row or col or enter `q` to quit.'
        );
    var input = '', letter, num, moves = 0;
    while (boardToString(targetBoard) != boardToString(manipulatedBoard) && input != 'q') {
        input = prompt(
            'Target:\n' + boardToString(targetBoard) +
            '\n\n\n' +
            'Board:\n' + boardToString(manipulatedBoard)
            );
        try {
            letter = input.charAt(0);
            num = parseInt(input.slice(1));
            if (letter == 'q')
				break;
            if (isNaN(num)
                || (letter != 'r' && letter != 'c')
                || (letter == 'r' && num >= rows)
                || (letter == 'c' && num >= cols)
                ) {
                throw new Error('');
            }
            if (letter == 'r') {
                flipRow(manipulatedBoard, num);
            }
            else {
                flipCol(manipulatedBoard, num);
            }
            moves++;
        }
        catch(e) {
            alert('Uh-oh, there seems to have been an input error');
        }
    }
    if (input == 'q') {
        alert('~~ Thanks for playing ~~');
    }
    else {
        alert('Completed in ' + moves + ' moves.');
    }
}


module FlippingBitsGame

using Printf, Random
import Base.size, Base.show, Base.==

struct Configuration
    M::BitMatrix
end

Base.size(c::Configuration) = size(c.M)
function Base.show(io::IO, conf::Configuration)
    M = conf.M
    nrow, ncol = size(M)
    print(io, " " ^ 3)
    for c in 1:ncol
        @printf(io, "%3i", c)
    end
    println(io, "\n", " " ^ 4, "-" ^ 3ncol)
    for r in 1:nrow
        @printf(io, "%2i |", r)
        for c in 1:ncol
            @printf(io, "%2c ", ifelse(M[r, c], 'T', 'F'))
        end
        println(io)
    end
    return nothing
end
Base.:(==)(a::Configuration, b::Configuration) = a.M == b.M

struct Index{D}
    i::Int
end
const ColIndex = Index{:C}
const RowIndex = Index{:R}

function flipbits!(conf::Configuration, c::ColIndex)
    col = @view conf.M[:, c.i]
    @. col = !col
    return conf
end
function flipbits!(conf::Configuration, r::RowIndex)
    row = @view conf.M[r.i, :]
    @. row = !row
    return conf
end

randomconfig(nrow::Integer, ncol::Integer) = Configuration(bitrand(nrow, ncol))

function randommoves!(conf::Configuration, nflips::Integer)
    nrow, ncol = size(conf)
    for _ in Base.OneTo(nflips)
        if rand() < 0.5
            flipbits!(conf, ColIndex(rand(1:ncol)))
        else
            flipbits!(conf, RowIndex(rand(1:nrow)))
        end
    end
    return conf
end

function play()
    nrow::Int, ncol::Int = 0, 0
    while nrow < 2 || ncol < 2
        print("Insert the size of the matrix (nrow [> 1] *space* ncol [> 1]):")
        nrow, ncol = parse.(Int, split(readline()))
    end
    mat = randomconfig(nrow, ncol)
    obj = deepcopy(mat)
    randommoves!(obj, 100)
    nflips = 0
    while mat != obj
        println("\n", nflips, " flips until now.")
        println("Current configuration:")
        println(mat)
        println("Objective configuration:")
        println(obj)
        print("Insert R[ind] to flip row, C[ind] to flip a column, Q to quit: ")
        line  = readline()
        input = match(r"([qrc])(\d+)"i, line)
        if input ≢ nothing && all(input.captures .≢ nothing)
            dim = Symbol(uppercase(input.captures[1]))
            ind = Index{dim}(parse(Int, input.captures[2]))
            flipbits!(mat, ind)
            nflips += 1
        elseif occursin("q", line)
            println("\nSEE YOU SOON!")
            return
        else
            println("\nINPUT NOT VALID, RETRY!\n")
        end
    end
    println("\nSUCCED! In ", nflips, " flips.")
    println(mat)
    return
end

end  # module FlippingBitsGame

using .FlippingBitsGame

FlippingBitsGame.play()


// version 1.1.3

import java.util.Random

val rand = Random()
val target = Array(3) { IntArray(3) { rand.nextInt(2) } }
val board  = Array(3) { IntArray(3) }

fun flipRow(r: Int) {
    for (c in 0..2) board[r][c] = if (board[r][c] == 0) 1 else 0
}

fun flipCol(c: Int) {
    for (r in 0..2) board[r][c] = if (board[r][c] == 0) 1 else 0
}

/** starting from the target we make 9 random row or column flips */
fun initBoard() {
    for (i in 0..2) {
        for (j in 0..2) board[i][j] = target[i][j]
    }
    repeat(9) {
        val rc = rand.nextInt(2)
        if (rc == 0)
            flipRow(rand.nextInt(3))
        else
            flipCol(rand.nextInt(3))
    }
}

fun printBoard(label: String, isTarget: Boolean = false) {
    val a = if (isTarget) target else board
    println("$label:")
    println("  | a b c")
    println("---------")
    for (r in 0..2) {
        print("${r + 1} |")
        for (c in 0..2) print(" ${a[r][c]}")
        println()
    }
    println()
}

fun gameOver(): Boolean {
    for (r in 0..2) {
        for (c in 0..2) if (board[r][c] != target[r][c]) return false
    }
    return true
}

fun main(args: Array<String>) {
     // initialize board and ensure it differs from the target i.e. game not already over!
    do {
        initBoard()
    }
    while(gameOver())

    printBoard("TARGET", true)
    printBoard("OPENING BOARD")
    var flips = 0

    do {
        var isRow = true
        var n = -1
        do {
            print("Enter row number or column letter to be flipped: ")
            val input = readLine()!!
            val ch = if (input.isNotEmpty()) input[0].toLowerCase() else '0'
            if (ch !in "123abc") {
                println("Must be 1, 2, 3, a, b or c")
                continue
            }
            if (ch in '1'..'3') {
                n = ch.toInt() - 49
            }
            else {
                isRow = false
                n = ch.toInt() - 97
            }
        }
        while (n == -1)

        flips++
        if (isRow) flipRow(n) else flipCol(n)
        val plural = if (flips == 1) "" else "S"
        printBoard("\nBOARD AFTER $flips FLIP$plural")
    }
    while (!gameOver())

    val plural = if (flips == 1) "" else "s"
    println("You've succeeded in $flips flip$plural")
}


target, board, moves, W, H = {}, {}, 0, 3, 3

function getIndex( i, j ) return i + j * W - W end

function flip( d, r )
    function invert( a ) if a == 1 then return 0 end return 1 end
    local idx
    if d == 1 then
        for i = 1, W do
            idx = getIndex( i, r )
            board[idx] = invert( board[idx] )
        end
    else
        for i = 1, H do
            idx = getIndex( r, i )
            board[idx] = invert( board[idx] )
        end
    end
    moves = moves + 1
end
function createTarget()
    target, board = {}, {}
    local idx
    for j = 1, H do
        for i = 1, W do
            idx = getIndex( i, j )
            if math.random() < .5 then target[idx] = 0
            else target[idx] = 1
            end
            board[idx] = target[idx]
        end
    end
    for i = 1, 103 do
        if math.random() < .5 then flip( 1, math.random( H ) )
        else flip( 2, math.random( W ) )
        end
    end
    moves = 0
end
function getUserInput()
    io.write( "Input row and/or column: " ); local r = io.read()
    local a
    for i = 1, #r do
        a = string.byte( r:sub( i, i ):lower() )
        if a >= 48 and a <= 57 then flip( 2, a - 48 ) end
        if a >= 97 and a <= string.byte( 'z' ) then flip( 1, a - 96 ) end
    end
end
function solved()
    local idx
    for j = 1, H do
        for i = 1, W do
            idx = getIndex( i, j )
            if target[idx] ~= board[idx] then return false end
        end
    end
    return true
end
function display()
    local idx
    io.write( "\nTARGET\n   " )
    for i = 1, W do io.write( string.format( "%d  ", i ) ) end; print()
    for j = 1, H do
        io.write( string.format( "%s  ", string.char( 96 + j ) ) )
        for i = 1, W do
            idx = getIndex( i, j )
            io.write( string.format( "%d  ", target[idx] ) )
        end; io.write( "\n" )
    end
    io.write( "\nBOARD\n   " )
    for i = 1, W do io.write( string.format( "%d  ", i ) ) end; print()
    for j = 1, H do
        io.write( string.format( "%s  ", string.char( 96 + j ) ) )
        for i = 1, W do
            idx = getIndex( i, j )
            io.write( string.format( "%d  ", board[idx] ) )
        end; io.write( "\n" )
    end
    io.write( string.format( "Moves: %d\n", moves ) )
end
function play()
    while true do
        createTarget()
        repeat
            display()
            getUserInput()
        until solved()
        display()
        io.write( "Very well!\nPlay again(Y/N)? " );
        if io.read():lower() ~= "y" then return end
    end
end
--[[entry point]]--
math.randomseed( os.time() )
play()


FlippingBits := module()
	export ModuleApply;
	local gameSetup, flip, printGrid, checkInput;
	local board;

	gameSetup := proc(n)
		local r, c, i, toFlip, target;
		randomize():
		target := Array( 1..n, 1..n, rand(0..1) );
		board := copy(target);
		for i to rand(3..9)() do
			toFlip := [0, 0];
			toFlip[1] := StringTools[Random](1, "rc");
			toFlip[2] := convert(rand(1..n)(), string);
			flip(toFlip);
		end do;
		return target;
	end proc;

	flip := proc(line)
		local i, lineNum;
		lineNum := parse(op(line[2..-1]));
		for i to upperbound(board)[1] do
			if line[1] = "R" then
				board[lineNum, i] := `if`(board[lineNum, i] = 0, 1, 0);
			else
				board[i, lineNum] := `if`(board[i, lineNum] = 0, 1, 0);
			end if;
		end do;
		return NULL;
	end proc;

	printGrid := proc(grid)
		local r, c;
		for r to upperbound(board)[1] do
			for c to upperbound(board)[1] do
				printf("%a ", grid[r, c]);
			end do;
			printf("\n");
		end do;
		printf("\n");
		return NULL;
	end proc;

	checkInput := proc(input)
		try
			if input[1] = "" then
				return false, "";
			elif not input[1] = "R" and not input[1] = "C" then
				return false, "Please start with 'r' or 'c'.";
			elif not type(parse(op(input[2..-1])), posint) then
				error;
			elif parse(op(input[2..-1])) < 1 or parse(op(input[2..-1])) > upperbound(board)[1] then
				return false, "Row or column number too large or too small.";
			end if;
		catch:
			return false, "Please indicate a row or column number."
		end try;
		return true, "";
	end proc;

	ModuleApply := proc(n)
		local gameOver, toFlip, target, answer, restart;
		restart := true;
		while restart do
			target := gameSetup(n);
			while ArrayTools[IsEqual](target, board) do
				target := gameSetup(n);
			end do;
			gameOver := false;
			while not gameOver do
				printf("The Target:\n");
				printGrid(target);
				printf("The Board:\n");
				printGrid(board);
				if ArrayTools[IsEqual](target, board) then
					printf("You win!! Press enter to play again or type END to quit.\n\n");
					answer := StringTools[UpperCase](readline());
					gameOver := true;
					if answer = "END" then
						restart := false
					end if;
				else
					toFlip := ["", ""];
					while not checkInput(toFlip)[1]  and not gameOver do
						ifelse (not op(checkInput(toFlip)[2..-1]) = "", printf("%s\n\n", op(checkInput(toFlip)[2..-1])), NULL);
						printf("Please enter a row or column to flip. (ex: r1 or c2) Press enter for a new game or type END to quit.\n\n");
						answer := StringTools[UpperCase](readline());
						if answer = "END" or answer = "" then
							gameOver := true;
							if answer = "END" then
								restart := false;
							end if;
						end if;
						toFlip := [substring(answer, 1), substring(answer, 2..-1)];
					end do;
					if not gameOver then
						flip(toFlip);
					end if;
				end if;
			end do;
		end do;
		printf("Game Over!\n");
	end proc;
end module:

FlippingBits(3);


ClearAll[PermuteState]
PermuteState[state_, {rc_, n_Integer}] := Module[{s},
  s = state;
  Switch[rc, "R",
   s[[n]] = 1 - s[[n]],
   "C",
   s[[All, n]] = 1 - s[[All, n]]
   ];
  s
  ]
SeedRandom[1337];
n = 3;
goalstate = state = RandomChoice[{0, 1}, {n, n}];
While[goalstate == state,
  permutations = {RandomChoice[{"C", "R"}, 20], RandomInteger[{1, n}, 20]} // Transpose;
  state = Fold[PermuteState, state, permutations];
];
i = 0;
history = {state};
Grid[goalstate, ItemSize -> {5, 3}, Frame -> True]
b1 = Button["", state = PermuteState[state, {"C", #}];
     AppendTo[history, state]; i++;
     If[state === goalstate, MessageDialog["You Won!"];
      Print[Grid[#, Frame -> True]] & /@ history]] & /@ Range[n];
b2 = Button["", state = PermuteState[state, {"R", #}];
     AppendTo[history, state]; i++;
     If[state === goalstate, MessageDialog["You Won!"];
      Print[Grid[#, Frame -> True]] & /@ history]] & /@ Range[n];
Dynamic[Grid[
  Prepend[MapThread[Prepend, {state, b2}],
   Prepend[b1, Row[{"Flips: ", i}]]], Frame -> True
]]


function FlippingBitsGame(n)
% Play the flipping bits game on an n x n array

    % Generate random target array
    fprintf('Welcome to the Flipping Bits Game!\n')
    if nargin < 1
        n = input('What dimension array should we use? ');
    end
    Tar = logical(randi([0 1], n));

    % Generate starting array by randomly flipping rows or columns
    Cur = Tar;
    while all(Cur(:) == Tar(:))
        nFlips = randi([3*n max(10*n, 100)]);
        randDim = randi([0 1], nFlips, 1);
        randIdx = randi([1 n], nFlips, 1);
        for k = 1:nFlips
            if randDim(k)
                Cur(randIdx(k), :) = ~Cur(randIdx(k), :);
            else
                Cur(:, randIdx(k)) = ~Cur(:, randIdx(k));
            end
        end
    end

    % Print rules
    fprintf('Given a %d x %d logical array,\n', n, n)
    fprintf('and a target array configuration,\n')
    fprintf('attempt to transform the array to the target\n')
    fprintf('by inverting the bits in a whole row or column\n')
    fprintf('at once in as few moves as possible.\n')
    fprintf('Enter the corresponding letter to invert a column,\n')
    fprintf('or the corresponding number to invert a row.\n')
    fprintf('0 will reprint the target array, and no entry quits.\n\n')
    fprintf('Target:\n')
    PrintArray(Tar)

    % Play until player wins or quits
    move = true;
    nMoves = 0;
    while ~isempty(move) && any(Cur(:) ~= Tar(:))
        fprintf('Move %d:\n', nMoves)
        PrintArray(Cur)
        move = lower(input('Enter move: ', 's'));
        if length(move) > 1
            fprintf('Invalid move, try again\n')
        elseif move
            r = str2double(move);
            if isnan(r)
                c = move-96;
                if c > n || c < 1
                    fprintf('Invalid move, try again\n')
                else
                    Cur(:, c) = ~Cur(:, c);
                    nMoves = nMoves+1;
                end
            else
                if r > n || r < 0
                    fprintf('Invalid move, try again\n')
                elseif r == 0
                    fprintf('Target:\n')
                    PrintArray(Tar)
                else
                    Cur(r, :) = ~Cur(r, :);
                    nMoves = nMoves+1;
                end
            end
        end
    end

    if all(Cur(:) == Tar(:))
        fprintf('You win in %d moves! Try not to flip out!\n', nMoves)
    else
        fprintf('Quitting? The challenge a bit much for you?\n')
    end
end

function PrintArray(A)
    [nRows, nCols] = size(A);
    fprintf('        ')
    fprintf(' %c', (1:nCols)+96)
    fprintf('\n')
    for r = 1:nRows
        fprintf('%8d%s\n', r, sprintf(' %d', A(r, :)))
    end
    fprintf('\n')
end


// Flipping Bits game.
// Transform a start grid to an end grid by flipping rows or columns.

size = 3

board = []
goal = []
for i in range(1,size)
    row = []
    for j in range(1,size)
        row.push (rnd > 0.5)
    end for
    board.push row
    goal.push row[0:]
end for

flipRow = function(n)
    for j in range(0, size-1)
        board[n-1][j] = not board[n-1][j]
    end for
end function

flipCol = function(n)
    for i in range(0, size-1)
        board[i][n-1] = not board[i][n-1]
    end for
end function

flipAny = function(s)
    s = s[0].upper
    if s >= "A" then flipCol s.code - 64 else flipRow val(s)
end function

for scramble in range(20)
    if rnd < 0.5 then flipRow ceil(rnd*size) else flipCol ceil(rnd*size)
end for

solved = function()
    for i in range(0, size-1)
        for j in range(0, size-1)
            if board[i][j] != goal[i][j] then return false
        end for
    end for
    return true
end function

moveCount = 0
while true
    print "  CURRENT:" + " "*(4+size*3) + "GOAL:"
    for i in range(1,size)
        s = i + " " + str(board[i-1])
        s = s + " "*(3+size*3) + str(goal[i-1])
        print s
    end for
    s = "   "
    for i in range(1,size)
        s = s + char(64+i) + "  "
    end for
    print s
    if solved then break
    moveCount = moveCount + 1
    inp = input("Move " + moveCount + "? ")
    flipAny(inp)
end while
print "You did it!"


import random, strformat, strutils

type
  Bit = range[0..1]
  Board = array[3, array[3, Bit]]

#---------------------------------------------------------------------------------------------------

func flipRow(board: var Board; row: int) =
  for cell in board[row].mitems:
    cell = 1 - cell

#---------------------------------------------------------------------------------------------------

func flipCol(board: var Board; col: int) =
  for row in board.mitems:
    row[col] = 1 - row[col]

#---------------------------------------------------------------------------------------------------

proc initBoard(target: Board): Board =

  # Starting from the target we make 9 random row or column flips.
  result = target
  for _ in 1..9:
    if rand(1) == 0:
      result.flipRow(rand(2))
    else:
      result.flipCol(rand(2))

#---------------------------------------------------------------------------------------------------

proc print(board: Board; label: string) =

  echo &"{label}:"
  echo "  | a b c"
  echo "---------"
  for r, row in board:
    stdout.write &"{r + 1} |"
    for cell in row: stdout.write &" {cell}"
    echo ""
  echo ""

#———————————————————————————————————————————————————————————————————————————————————————————————————

var target, board: Board

randomize()

# Initialize target.
for row in target.mitems:
  for cell in row.mitems:
    cell = rand(1)

# Initialize board and ensure it differs from the target i.e. game not already over!
while true:
  board = initBoard(target)
  if board != target:
    break

target.print("TARGET")
board.print("OPENING BOARD")

var flips = 0
while board != target:

  # Get input from player.
  var isRow = true
  var n = -1
  while n < 0:
    stdout.write "Enter row number or column letter to be flipped: "
    stdout.flushFile()
    let input = stdin.readLine()
    let ch = if input.len > 0: input[0].toLowerAscii else: '0'
    if ch notin "123abc":
      echo "Must be 1, 2, 3, a, b or c"
      continue
    if ch in '1'..'3':
      n = ord(ch) - ord('1')
    else:
      isRow = false
      n = ord(ch) - ord('a')

  # Update board.
  inc flips
  if isRow: board.flipRow(n) else: board.flipCol(n)
  target.print("\nTARGET")
  let plural = if flips == 1: "" else: "S"
  board.print(&"BOARD AFTER {flips} FLIP{plural}")

let plural = if flips == 1: "" else: "s"
echo &"You’ve succeeded in {flips} flip{plural}"


module FlipGame =
struct
  type t = bool array array

  let make side = Array.make_matrix side side false

  let flipcol b n =
    for i = 0 to (Array.length b - 1) do
      b.(n).(i) <- not b.(n).(i)
    done

  let fliprow b n =
    for i = 0 to (Array.length b - 1) do
      b.(i).(n) <- not b.(i).(n)
    done

  let randflip b =
    let n = Random.int (Array.length b - 1) in
    match Random.bool () with
    | true -> fliprow b n
    | false -> flipcol b n

  let rec game side steps =
    let start, target = make side, make side in
    for i = 1 to steps do
      randflip start;
      randflip target
    done;
    if start = target then game side steps (* try again *) else
      (start, target)

  let print b =
    for i = 0 to Array.length b - 1 do
      for j = 0 to Array.length b - 1 do
        Printf.printf " %d " (if b.(j).(i) then 1 else 0)
      done;
      print_newline ()
    done;
    print_newline ()

  let draw_game board target =
    print_endline "TARGET"; print target;
    print_endline "BOARD"; print board
end

let play () =
  let module G = FlipGame in
  let board, target = G.game 3 10 in
  let steps = ref 0 in
  while board <> target do
    G.draw_game board target;
    print_string "> ";
    flush stdout;
    incr steps;
    match String.split_on_char ' ' (read_line ()) with
    | ["row"; row] ->
      (match int_of_string_opt row with
       | Some n -> G.fliprow board n
       | None -> print_endline "(nothing happens)")
    | ["col"; col] ->
      (match int_of_string_opt col with
       | Some n -> G.flipcol board n
       | None -> print_endline "(nothing happens)")
    | _ -> ()
  done;
  G.draw_game board target;
  Printf.printf "\n\nGame solved in %d steps\n" !steps

let () =
  if not !Sys.interactive then
    (Random.self_init ();
      play ())


#!perl
use strict;
use warnings qw(FATAL all);

my $n = shift(@ARGV) || 4;
if( $n < 2 or $n > 26 ) {
	die "You can't play a size $n game\n";
}

my $n2 = $n*$n;

my (@rows, @cols);
for my $i ( 0 .. $n-1 ) {
	my $row = my $col = "\x00" x $n2;
	vec($row, $i * $n + $_, 8) ^= 1 for 0 .. $n-1;
	vec($col, $i + $_ * $n, 8) ^= 1 for 0 .. $n-1;
	push @rows, $row;
	push @cols, $col;
}

my $goal = "0" x $n2;
int(rand(2)) or (vec($goal, $_, 8) ^= 1) for 0 .. $n2-1;
my $start = $goal;
{
	for(@rows, @cols) {
		$start ^= $_ if int rand 2;
	}
	redo if $start eq $goal;
}

my @letters = ('a'..'z')[0..$n-1];
sub to_strings {
	my $board = shift;
	my @result = join(" ", "  ", @letters);
	for( 0 .. $n-1 ) {
		my $res = sprintf("%2d ",$_+1);
		$res .= join " ", split //, substr $board, $_*$n, $n;
		push @result, $res;
	}
	\@result;
}

my $fmt;
my ($stext, $etext) = ("Starting board", "Ending board");
my $re = join "|", reverse 1 .. $n, @letters;
my $moves_so_far = 0;
while( 1 ) {
	my ($from, $to) = (to_strings($start), to_strings($goal));
	unless( $fmt ) {
		my $len = length $from->[0];
		$len = length($stext) if $len < length $stext;
		$fmt = join($len, "%", "s%", "s\n");
	}
	printf $fmt, $stext, $etext;
	printf $fmt, $from->[$_], $to->[$_] for 0 .. $n;
	last if $start eq $goal;
	INPUT_LOOP: {
		printf "Move #%s: Type one or more row numbers and/or column letters: ",
			$moves_so_far+1;
		my $input = <>;
		die unless defined $input;
		my $did_one;
		for( $input =~ /($re)/gi ) {
			$did_one = 1;
			if( /\d/ ) {
				$start ^= $rows[$_-1];
			} else {
				$_ = ord(lc) - ord('a');
				$start ^= $cols[$_];
			}
			++$moves_so_far;
		}
		redo INPUT_LOOP unless $did_one;
	}
}
print "You won after $moves_so_far moves.\n";


integer w, h

string board, target

procedure new_board()
    board = ""
    h = prompt_number("Enter number of rows(1..9):",{1,9})
    w = prompt_number("Enter number of columns(1..26):",{1,26})
    string line = ""
    for j=1 to w do line &= 'A'+j-1 end for
    board = "  "&line&"\n"
    for i=1 to h do
        line = '0'+i&" "
        for j=1 to w do line &= '0'+rand(2)-1 end for
        board &= line&"\n"
    end for
end procedure

procedure show_bt()
sequence sb = split(board,'\n'),
         st = split(target,'\n')
    printf(1,"board:%s     target:%s\n",{sb[1],st[1]})
    for i=2 to length(sb)-1 do
        printf(1,"      %s            %s\n",{sb[i],st[i]})
    end for
end procedure

procedure flip(integer ch, bool bShow=true)
integer k
    if ch>='A' and ch<='A'+w-1 then
        -- flip_column
        ch = ch-'A'+1
        for i=1 to h do
            k = 2+ch+i*(w+3)
            board[k] = '0'+'1'-board[k]
        end for
        k = 2+ch
    elsif ch>='1' and ch<='0'+h then
        -- flip_row
        ch -= '0'
        for i=1 to w do
            k = 2+i+(ch)*(w+3)
            board[k] = '0'+'1'-board[k]
        end for
        k = 1+(ch)*(w+3)
    else
        ?9/0    -- sanity check
    end if
    if bShow then
        integer wasch = board[k]
        board[k] = '*'
        show_bt()
        board[k] = wasch
    end if
end procedure

procedure scramble_board()
integer lim = 10000
    while 1 do
        for i=1 to lim do
            if rand(2)=1 then
                flip('A'-1+rand(w),false)
            else
                flip('0'+rand(h),false)
            end if
        end for
        if board!=target then exit end if
        lim -= 1 -- sidestep the degenerate 1x1 case
    end while
end procedure

function solve_board()
-- not guaranteed optimal (the commented-out length check clogs it on larger boards)
string original = board, moves
sequence next = {{0,board,""}},
         legal_moves = tagset('A'+w-1,'A')&tagset('0'+h,'1')
atom t2 = time()+2 -- in case board is illegal/unsolveable
    while time()<t2 do
        for lm=1 to length(legal_moves) do
            integer c = legal_moves[lm]
            {?,board,moves} = next[1]
            flip(c,false)
            moves &= c
            if board = target then
                board = original
                return moves
            end if
            next = append(next,{sum(sq_eq(board,target)),board,moves})
            for i=length(next) to 3 by -1 do
                if next[i][1]<=next[i-1][1] then exit end if
--              if length(next[i][3])>length(next[i-1][3]) then exit end if
                {next[i-1],next[i]} = {next[i],next[i-1]}
            end for
        end for
        next = next[2..$]
    end while
    board = original
    return 0
end function

constant ESC = #1B

procedure main()
    integer moves = 0, solves = 0, ch
    bool took_hint = false
    new_board()
    target = board
    scramble_board()
    show_bt()
    object soln = solve_board()
    while 1 do
        string solve = iff(string(soln)?sprintf(" solveable in %d,",length(soln)):"")
        printf(1,"moves taken %d,%s enter your move (A..%c or 1..%c) or ?:",{moves,solve,'A'+w-1,'0'+h})
        while 1 do
            ch = upper(wait_key())
            if ch<=#FF then exit end if -- (ignore control keys)
        end while
        printf(1,"%c\n",ch)
        if (ch>='A' and ch<='A'+w-1)
        or (ch>='1' and ch<='0'+h) then
            flip(ch)
            if board=target then
                printf(1,"\nWell %s!\n\n",{iff(took_hint?"cheated","done")})
                exit
            end if
            moves += 1
            soln = iff(string(soln) and ch=soln[1]?soln[2..$]:solve_board())
        elsif string(soln) and
             (ch='H' -- (nb consumed above if w>=8)
           or ch='.') then
            took_hint = true
            printf(1,"hint: %c\n",soln[1])
        elsif ch='Q' -- (nb consumed above if w>=17)
           or ch=ESC then
            exit
        elsif string(soln) and
             (ch='S' -- (nb consumed above if w>=19)
           or ch='!') then
            for i=1 to length(soln) do
                printf(1,"auto-solving, move %d:\n",i)
                flip(soln[i])
                sleep(2)
            end for
            exit
        else
            puts(1,"press ")
            if string(soln) then
                puts(1,"'!' (or 's' if width<19) to solve the board automatically,\n")
                puts(1,"      '.' (or 'h' if width<8) to show hint,\n")
            end if
            puts(1,"      escape (or 'q' if width<17) to quit\n")
        end if
    end while
end procedure
main()


(subscriptrange, stringrange, stringsize):
flip: procedure options (main);
   declare n fixed binary;

   put skip list ('This is the bit-flipping game.  What size of board do you want?');
   get list (n);
   put skip list
      ('Your task is to change your board so as match the board on the right (the objective)');

   begin;
      declare initial(n,n) bit (1), objective(n,n) bit (1);
      declare (i, j, k, move) fixed binary;
      declare ch character(1);
      declare alphabet character (26) initial ('abcdefghijklmnopqrstuvwxyz');

      on subrg
         begin; put skip list ('Your row or column ' || trim(ch) || ' is out of range'); stop; end;

      initial, objective = iand(random()*99, 1) = 1;

      /* Set up the objective array: */
      do i = 1 to n-1;
         j = random()*n+1;  objective(j,*) = ^objective(j,*);
         j = random()*n+1;  objective(*,j) = ^objective(*,j);
      end;

      do move = 0 by 1;
         put skip edit ( center('You', n*3), center('The objective', 3*n+4) ) (x(3), a);
         put skip edit ( (substr(alphabet, i, 1) do i = 1 to n) ) (x(5), (n) a(3));
         put      edit ( (substr(alphabet, i, 1) do i = 1 to n) ) (x(3), (n) a(3));
         do i = 1 to n;
            put skip edit (i, initial(i,*), objective(i,*)) ((n+1) f(3), x(3), (n) F(3));
         end;

         if all(initial = objective) then leave;

         put skip(2) list
            ('Please type a row number or column letter whose bits you want to flip: ');
         get edit (ch) (L); put edit (ch) (a);
         k = index(alphabet, ch);
         if k > 0 then
            initial(*, k) = ^initial(*,k); /* Flip column k */
         else
            initial(ch,*) = ^initial(ch,*); /* Flip row ch */
      end;
      put skip(2) list ('Congratulations. You solved it in ' || trim(move) || ' moves.');
   end;

end flip;


"""
Given a %i by %i sqare array of zeroes or ones in an initial
configuration, and a target configuration of zeroes and ones
The task is to transform one to the other in as few moves as
possible by inverting whole numbered rows or whole lettered
columns at once.
In an inversion any 1 becomes 0 and any 0 becomes 1 for that
whole row or column.

"""

from random import randrange
from copy import deepcopy
from string import ascii_lowercase

try:    # 2to3 fix
    input = raw_input
except:
    pass

N = 3   # N x N Square arrray

board  = [[0]* N for i in range(N)]

def setbits(board, count=1):
    for i in range(count):
        board[randrange(N)][randrange(N)] ^= 1

def shuffle(board, count=1):
    for i in range(count):
        if randrange(0, 2):
            fliprow(randrange(N))
        else:
            flipcol(randrange(N))

def pr(board, comment=''):
    print(str(comment))
    print('     ' + ' '.join(ascii_lowercase[i] for i in range(N)))
    print('  ' + '\n  '.join(' '.join(['%2s' % j] + [str(i) for i in line])
                             for j, line in enumerate(board, 1)))

def init(board):
    setbits(board, count=randrange(N)+1)
    target = deepcopy(board)
    while board == target:
        shuffle(board, count=2 * N)
    prompt = '  X, T, or 1-%i / %s-%s to flip: ' % (N, ascii_lowercase[0],
                                                    ascii_lowercase[N-1])
    return target, prompt

def fliprow(i):
    board[i-1][:] = [x ^ 1 for x in board[i-1] ]

def flipcol(i):
    for row in board:
        row[i] ^= 1

if __name__ == '__main__':
    print(__doc__ % (N, N))
    target, prompt = init(board)
    pr(target, 'Target configuration is:')
    print('')
    turns = 0
    while board != target:
        turns += 1
        pr(board, '%i:' % turns)
        ans = input(prompt).strip()
        if (len(ans) == 1
            and ans in ascii_lowercase and ascii_lowercase.index(ans) < N):
            flipcol(ascii_lowercase.index(ans))
        elif ans and all(ch in '0123456789' for ch in ans) and 1 <= int(ans) <= N:
            fliprow(int(ans))
        elif ans == 'T':
            pr(target, 'Target configuration is:')
            turns -= 1
        elif ans == 'X':
            break
        else:
            print("  I don't understand %r... Try again. "
                  "(X to exit or T to show target)\n" % ans[:9])
            turns -= 1
    else:
        print('\nWell done!\nBye.')


RANDOMIZE TIMER
DIM SHARED cellsPerSide, legalMoves$, startB$, currentB$, targetB$, moveCount

restart
DO
    displayStatus
    IF currentB$ = targetB$ THEN 'game done!
        PRINT " Congratulations, done in"; moveCount; " moves."
        PRINT "": PRINT " Press y for yes, if you want to start over > ";
        yes$ = getKey$: PRINT yes$: _DELAY .4: vcls
        IF yes$ = "y" THEN restart ELSE nomore = -1
    ELSE 'get next move
        m$ = " ": PRINT
        WHILE INSTR(legalMoves$, m$) = 0
            PRINT " Press a lettered column or a numbered row to flip (or 0,q,?,!) > ";
            m$ = getKey$: PRINT m$: _DELAY .4
            IF m$ = "!" THEN
                showSolution = -1: m$ = " ": EXIT WHILE
            ELSEIF m$ = "?" THEN: m$ = " ": cp CSRLIN, "Hint: " + hint$
            ELSEIF m$ = "0" OR m$ = "q" THEN: vcls: CLOSE: END
            ELSEIF m$ = "" THEN: m$ = " "
            END IF
        WEND
        IF showSolution THEN 'run the solution from hints function
            showSolution = 0: mv$ = hint$
            cp CSRLIN + 1, "For the next move, the AI has chosen: " + mv$
            cp CSRLIN + 1, "Running the solution with 4 sec screen delays..."
            _DELAY 4: vcls
            WHILE mv$ <> "Done?"
                moveCount = moveCount + 1: makeMove mv$: displayStatus: mv$ = hint$
                cp CSRLIN + 1, "For the next move, the AI has chosen: " + mv$
                cp CSRLIN + 1, "Running the solution with 4 sec screen delays..."
                _DELAY 4: vcls
            WEND
            displayStatus
            cp CSRLIN + 1, "Done! Current board matches Target"
            cp CSRLIN + 1, "Press y for yes, if you want to start over: > "
            yes$ = getKey$: PRINT yes$: _DELAY .4: vcls
            IF yes$ = "y" THEN restart ELSE nomore = -1
        ELSE
            vcls: moveCount = moveCount + 1: makeMove m$
        END IF
    END IF
LOOP UNTIL nomore
CLOSE

SUB displayStatus
    COLOR 9: showBoard 2, 2, currentB$, "Current:"
    COLOR 12: showBoard 2, 2 + 2 * cellsPerSide + 6, targetB$, "Target:"
    COLOR 13: PRINT: PRINT " Number of moves taken so far is" + STR$(moveCount)
    COLOR 14
END SUB

FUNCTION hint$ 'compare the currentB to targetB and suggest letter or digit or done
    FOR i = 1 TO 2 * cellsPerSide 'check cols first then rows as listed in legalMoves$
        r$ = MID$(legalMoves$, i, 1)
        IF i <= cellsPerSide THEN
            currentbit$ = MID$(currentB$, i, 1): targetBit$ = MID$(targetB$, i, 1)
            IF currentbit$ <> targetBit$ THEN flag = -1: EXIT FOR
        ELSE
            j = i - cellsPerSide
            currentbit$ = MID$(currentB$, (j - 1) * cellsPerSide + 1, 1)
            targetBit$ = MID$(targetB$, (j - 1) * cellsPerSide + 1, 1)
            IF currentbit$ <> targetBit$ THEN flag = -1: EXIT FOR
        END IF
    NEXT
    IF flag THEN hint$ = r$ ELSE hint$ = "Done?"
END FUNCTION

SUB restart
    CLOSE
    OPEN "Copy Flipping Bits Game.txt" FOR OUTPUT AS #3
    cellsPerSide = 0: legalMoves$ = "": moveCount = 0
    COLOR 9: cp 3, "Flipping Bits Game, now with AI!  b+ 2017-12-18"
    COLOR 5
    cp 5, "You will be presented with a square board marked Current and"
    cp 6, "another marked Target. The object of the game is to match"
    cp 7, "the Current board to Target in the least amount of moves."
    cp 9, "To make a move, enter a letter for a column to flip or"
    cp 10, "a digit for a row to flip. In a flip, all 1's are"
    cp 11, "changed to 0's and all 0's changed to 1's."
    cp 13, "You may enter 0 or q at any time to quit."
    cp 14, "You may press ? when prompted for move to get a hint."
    cp 15, "You may press ! to have the program solve the puzzle."
    COLOR 14: PRINT: PRINT
    WHILE cellsPerSide < 2 OR cellsPerSide > 9
        LOCATE CSRLIN, 13: PRINT "Please press how many cells you want per side 2 to 9 > ";
        in$ = getKey$: PRINT in$: _DELAY .4
        IF in$ = "0" OR in$ = "q" THEN END ELSE cellsPerSide = VAL(in$)
    WEND
    vcls
    FOR i = 1 TO cellsPerSide: legalMoves$ = legalMoves$ + CHR$(96 + i): NEXT
    FOR i = 1 TO cellsPerSide: legalMoves$ = legalMoves$ + LTRIM$(STR$(i)): NEXT
    startB$ = startBoard$: currentB$ = startB$: targetB$ = makeTarget$: currentB$ = startB$
END SUB

FUNCTION startBoard$
    FOR i = 1 TO cellsPerSide ^ 2: r$ = r$ + LTRIM$(STR$(INT(RND * 2))): NEXT
    startBoard$ = r$
END FUNCTION

SUB showBoard (row, col, board$, title$)
    LOCATE row - 1, col: PRINT title$
    FOR i = 1 TO cellsPerSide
        LOCATE row, col + 2 * (i - 1) + 3: PRINT MID$(legalMoves$, i, 1);
    NEXT
    PRINT
    FOR i = 1 TO cellsPerSide
        LOCATE row + i, col - 1: PRINT STR$(i);
        FOR j = 1 TO cellsPerSide
            LOCATE row + i, col + 2 * j: PRINT " " + MID$(board$, (i - 1) * cellsPerSide + j, 1);
        NEXT
        PRINT
    NEXT
END SUB

SUB makeMove (move$)
    ac = ASC(move$)
    IF ac > 96 THEN 'letter
        col = ac - 96
        FOR i = 1 TO cellsPerSide
            bit$ = MID$(currentB$, (i - 1) * cellsPerSide + col, 1)
            IF bit$ = "0" THEN
                MID$(currentB$, (i - 1) * cellsPerSide + col, 1) = "1"
            ELSE
                MID$(currentB$, (i - 1) * cellsPerSide + col, 1) = "0"
            END IF
        NEXT
    ELSE 'number
        row = ac - 48
        FOR i = 1 TO cellsPerSide
            bit$ = MID$(currentB$, (row - 1) * cellsPerSide + i, 1)
            IF bit$ = "0" THEN
                MID$(currentB$, (row - 1) * cellsPerSide + i, 1) = "1"
            ELSE
                MID$(currentB$, (row - 1) * cellsPerSide + i, 1) = "0"
            END IF
        NEXT
    END IF
END SUB

FUNCTION makeTarget$
    WHILE currentB$ = startB$
        FOR i = 1 TO cellsPerSide * cellsPerSide
            m$ = MID$(legalMoves$, INT(RND * LEN(legalMoves$)) + 1, 1): makeMove m$
        NEXT
    WEND
    makeTarget$ = currentB$
END FUNCTION

SUB cp (row, text$) 'center print at row
    LOCATE row, (80 - LEN(text$)) / 2: PRINT text$;
END SUB

SUB vcls 'print the screen to file then clear it
    DIM s$(23)
    FOR lines = 1 TO 23
        FOR t = 1 TO 80: scan$ = scan$ + CHR$(SCREEN(lines, t)): NEXT
        s$(lines) = RTRIM$(scan$): scan$ = ""
    NEXT
    FOR fini = 23 TO 1 STEP -1
        IF s$(fini) <> "" THEN EXIT FOR
    NEXT
    PRINT #3, ""
    FOR i = 1 TO fini: PRINT #3, s$(i): NEXT
    PRINT #3, "": PRINT #3, STRING$(80, "-"): CLS
END SUB

FUNCTION getKey$ 'just want printable characters
    k$ = ""
    WHILE LEN(k$) = 0
        k$ = INKEY$
        IF LEN(k$) THEN 'press something so respond
            IF LEN(k$) = 2 OR ASC(k$) > 126 OR ASC(k$) < 32 THEN k$ = "*": BEEP
        END IF
    WEND
    getKey$ = k$
END FUNCTION


#lang racket
(define (flip-row! pzzl r)
  (define N (integer-sqrt (bytes-length pzzl)))
  (for* ((c (in-range N)))
    (define idx (+ c (* N r)))
    (bytes-set! pzzl idx (- 1 (bytes-ref pzzl idx)))))

(define (flip-col! pzzl c)
  (define N (integer-sqrt (bytes-length pzzl)))
  (for* ((r (in-range N)))
    (define idx (+ c (* N r)))
    (bytes-set! pzzl idx (- 1 (bytes-ref pzzl idx)))))

(define (new-game N (flips 10))
  (define N2 (sqr N))
  (define targ (list->bytes (for/list ((_ N2)) (random 2))))
  (define strt (bytes-copy targ))
  (for ((_ flips))
    (case (random 2)
      ((0) (flip-col! strt (random N)))
      ((1) (flip-row! strt (random N)))))
  (if (equal? strt targ) (new-game N) (values targ strt)))

(define (show-games #:sep (pzl-sep " | ") . pzzls)
  (define N (integer-sqrt (bytes-length (first pzzls))))
  (define caption (string-join (for/list ((c (in-range N))) (~a (add1 c))) ""))
  (define ruler   (string-join (for/list ((c (in-range N))) "-") ""))

  (define ((pzzle-row r) p)
    (string-join (for/list ((c (in-range N))) (~a (bytes-ref p (+ c (* N r))))) ""))

  (displayln
   (string-join
    (list*
     (format "  ~a" (string-join (for/list ((_ pzzls)) caption) pzl-sep))
     (format "  ~a" (string-join (for/list ((_ pzzls)) ruler) pzl-sep))
     (for/list ((r (in-range N)) (R (in-naturals (char->integer #\a))))
       (format "~a ~a" (integer->char R) (string-join (map (pzzle-row r) pzzls) pzl-sep))))
    "\n")))

(define (play N)
  (define-values (end start) (new-game N))
  (define (turn n (show? #t))
    (cond
      [(equal? end start) (printf "you won on turn #~a~%" n)]
      [else
       (when show? ;; don't show after whitespace
         (printf "turn #~a~%" n)
         (show-games start end))
       (match (read-char)
         [(? eof-object?) (printf "sad to see you go :-(~%")]
         [(? char-whitespace?) (turn n #f)]
         [(? char-numeric? c)
          (define cnum (- (char->integer c) (char->integer #\1)))
          (cond [(< -1 cnum N)
                 (printf "flipping col ~a~%" (add1 cnum))
                 (flip-col! start cnum)
                 (turn (add1 n))]
                [else (printf "column number out of range ~a > ~a~%" (add1 cnum) N)
                      (turn n)])]
         [(? char-lower-case? c)
          (define rnum (- (char->integer c) (char->integer #\a)))
          (cond [(< -1 rnum N)
                 (printf "flipping row ~a~%" (add1 rnum))
                 (flip-row! start rnum)
                 (turn (add1 n))]
                [else (printf "row number out of range ~a > ~a~%" (add1 rnum) (sub1 N))
                      (turn n)])]
         [else (printf "unrecognised character in input: ~s~%" else)
               (turn n)])]))
  (turn 0))


sub MAIN ($square = 4) {
    say "{$square}? Seriously?" and exit if $square < 1 or $square > 26;
    my %bits = map { $_ => %( map { $_ => 0 }, ('A' .. *)[^ $square] ) },
        (1 .. *)[^ $square];
    scramble %bits;
    my $target = build %bits;
    scramble %bits until build(%bits) ne $target;
    display($target, %bits);
    my $turns = 0;
    while my $flip = prompt "Turn {++$turns}: Flip which row / column? " {
        flip $flip.match(/\w/).uc, %bits;
        if display($target, %bits) {
            say "Hurray! You solved it in $turns turns.";
            last;
        }
    }
}

sub display($goal, %hash) {
    shell('clear');
    say "Goal\n$goal\nYou";
    my $this = build %hash;
    say $this;
    return ($goal eq $this);
}

sub flip ($a, %hash) {
    given $a {
        when any(keys %hash) {
            %hash{$a}{$_} = %hash{$a}{$_} +^ 1 for %hash{$a}.keys
        };
        when any(keys %hash{'1'}) {
            %hash{$_}{$a} = %hash{$_}{$a} +^ 1 for %hash.keys
        };
    }
}

sub build (%hash) {
    my $string = '   ';
    $string ~= sprintf "%2s ", $_ for sort keys %hash{'1'};
    $string ~= "\n";
    for %hash.keys.sort: +* -> $key {
        $string ~= sprintf "%2s ", $key;
        $string ~= sprintf "%2s ", %hash{$key}{$_} for sort keys %hash{$key};
        $string ~=  "\n";
    };
    $string
}

sub scramble(%hash) {
    my @keys = keys %hash;
    @keys.push: | keys %hash{'1'};
    flip $_,  %hash for @keys.pick( @keys/2 );
}


Red []
random/seed   now/time/precise                 ;; start random generator
kRows: kCols: 3                                ;; define board size, 3x3 upto 9x9 possible
                                               ;; create series of 3 empty blocks:
loop kRows [ append/only board: []  copy [] ]  ;; ( this is actually a bit tricky, normally you'd have to use "copy" [] inside a loop )

kValid: "1A"                                    ;; generate string for input validation "321ABC"
loop (kRows - 1 ) [insert kValid (first kValid) + 1 ]
loop (kCols - 1 ) [append kValid (last kValid) + 1 ]

repeat row kRows [ loop kCols [ append board/:row -1 + random 2 ] ] ;; fill board with random 0 / 1
;;--------------------------------------
xorme: func ['val][ set val 1 xor get val ]           ;; function: flip the given board position
;;--------------------------------------
flip: func [ what [string!] ] [                       ;; flip complete row or column  of board
 row:  -48 + to-integer first  what                   ;; convert string to integer row/column index
 if row <= kRows  [ repeat col kCols [ xorme board/:row/:col] return 0 ]
 repeat row2 kRows [ xorme board/:row2/(row - 16)]
]
;;--------------------------------------
showboard: func [title [string!] b] [                           ;; function: show board name + board or target
  prin [title newline newline" " letter: #"A" ]                 ;; ( prin doesn't print newline at end )
  loop ( kCols - 1) [ prin ["" letter: letter + 1] ] print ""   ;; print column letters
  repeat row kRows [                                            ;; print one row
    prin row                                                    ;; first print row number
    repeat col kCols [ prin ["" b/:row/:col ]]
    print ""
  ]
]

showboard "Target" target: copy/deep board               ;; create target as copy from board and show
random kvalid
repeat pos 3 [flip copy/part skip kvalid pos 1]          ;; now flip board 3 times at random row/column

run: -1
forever [
  showboard "Board" board
  if board = target [ Print ["You solved it in" run + 1 "move(s) !" ] halt ]          ;; count last move
  print [newline "moves:" run: run + 1   ]                                            ;; show moves taken so far
  until [ find kvalid inp: uppercase ask "Enter Row No or Column Letter to flip ?" ]  ;; read valid input character
  flip  inp
]                                                         ;; 42 lines :- )


/*REXX program presents a  "flipping bit"  puzzle.  The user can solve via it via  C.L. */
parse arg  N u seed .                            /*get optional arguments from the C.L. */
if N==''  |  N==","     then N=3                 /*Size given?   Then use default of  3.*/
if u==''  |  u==","     then u=N                 /*the number of bits initialized to ON.*/
if datatype(seed, 'W')  then call random ,,seed  /*is there a seed (for repeatability?) */
[email protected]= 'a b c d e f g h i j k l m n o p q r s t u v w x y z'     /*literal for column id.*/
cols=space([email protected], 0);        upper cols           /*letters to be used for the columns.  */
@.=0;  !.=0                                      /*set both arrays to  "off" characters.*/
tries=0                                          /*number of player's attempts (so far).*/
         do  while  show(0) < u                  /* [↓]   turn  "on"  U  number of bits.*/
         r=random(1, N);      c=random(1, N)     /*get a random  row  and  column.      */
         @.r.c=1       ;      !.r.c=1            /*set (both)  row and column  to ON.   */
         end   /*while*/                         /* [↑]  keep going 'til   U   bits set.*/
oz=z                                             /*save the original array string.      */
call show 1, '   ◄═══target═══╣', , 1            /*display the target for user to attain*/
       do random(1,2); call flip 'R',random(1,N) /*flip a   row    of  bits.            */
                       call flip 'C',random(1,N) /*  "  "  column   "    "              */
       end   /*random*/                          /* [↑]  just perform  1  or  2  times. */
if z==oz  then call flip 'R', random(1, N)       /*ensure it's not target we're flipping*/
       do  until  z==oz;      call prompt        /*prompt until they get it right.      */
       call flip left(?, 1),  substr(?, 2)       /*flip a user selected row or column.  */
       call show 0                               /*get image (Z) of the updated array.  */
       end   /*until*/
call show 1, '   ◄───your array'                 /*display the array to the terminal.   */
say '─────────Congrats!    You did it in'     tries     "tries."
exit tries                                       /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
halt:  say 'program was halted by user.';  exit  /*the REXX program was halted by user. */
hdr:   aaa=arg(1);  if oo==1  then aaa=translate(aaa, "╔═║", '┌─│');    say aaa;    return
isInt: return datatype( arg(1), 'W')             /*returns   1   if  arg  is an integer.*/
isLet: return datatype( arg(1), 'M')             /*returns   1   if  arg  is a letter.  */
terr:  if ok  then say  '───────── ***error***:  illegal'  arg(1);        ok=0;     return
/*──────────────────────────────────────────────────────────────────────────────────────*/
flip: arg x,#;   do c=1  for N  while x=='R';  @.#.c = \@.#.c;  end  /*c*/
                 do r=1  for N  while x=='C';  @.r.# = \@.r.#;  end  /*r*/;         return
/*──────────────────────────────────────────────────────────────────────────────────────*/
prompt: if tries\==0  then  say '─────────bit array after play: '         tries
        signal on halt                           /*another method for the player to quit*/
        !='─────────Please enter a    row number    or a    column letter,      or  Quit:'
        call show 1, '   ◄───your array'         /*display the array to the terminal.   */
           do forever  until ok;       ok=1;     say;     say !;     pull ?  _  .  1  aa
           if abbrev('QUIT', ?, 1)     then do;  say '─────────quitting···';  exit 0;  end
           if ?==''                    then do;  call show 1,"   ◄═══target═══╣",.,1; ok=0
                                                 call show 1,"   ◄───your array"
                                            end                       /* [↑] reshow targ*/
           if _ \== ''                 then call terr 'too many args entered:'   aa
           if \isInt(?) & \isLet(?)    then call terr 'row/column: '             ?
           if  isLet(?)                then a=pos(?, cols)
           if  isLet(?) & (a<1 | a>N | length(?)>1)  then call terr 'column: '   ?
           if  isLet(?)                then ?='C'pos(?, cols)
           if  isInt(?) & (?<1 | ?>N)  then call terr 'row: '                    ?
           if  isInt(?)                then ?='R' || (?/1)            /*normalize number*/
           end   /*forever*/                                          /*end of da checks*/
        tries= tries + 1                                              /*bump da counter.*/
        return ?                                                      /*return response.*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
show: $=0;              _=;            parse arg tell,tx,o,oo         /*$≡num of ON bits*/
      if tell  then do; say;     say '     '   subword([email protected], 1, N)   "  column letter"
                        call hdr 'row ┌'copies('─', N+N+1)            /*prepend col hdrs*/
                    end                                               /* [↑]  grid hdrs.*/
      z=                                                              /* [↓] build grid.*/
        do   r=1  for N                                               /*show  grid rows.*/
          do c=1  for N;  if o==.  then do;  z=z || !.r.c;  _=_ !.r.c;  $=$ + !.r.c;   end
                                   else do;  z=z || @.r.c;  _=_ @.r.c;  $=$ + @.r.c;   end
          end   /*c*/                                                 /*··· and sum ONs.*/
        if tx\==''  then tar.r=_ tx                                   /*build da target?*/
        if tell     then call hdr right(r, 2)   ' │'_   tx; _=        /*show the grid?  */
        end     /*r*/                                                 /*show a grid row.*/
      if tell  then say;                     return $                 /*show blank line?*/