Problem:
 Score : 400 points    Problem Statement A maze is composed of a grid of H \times W squares - H vertical, W horizontal.  The square at the i -th row from the top and the j -th column from the left - (i,j) - is a wall if S_{ij} is # and a road if S_{ij} is . .  There is a magician in (C_h,C_w) . He can do the following two kinds of moves:   Move A: Walk to a road square that is vertically or horizontally adjacent to the square he is currently in.  Move B: Use magic to warp himself to a road square in the 5\times 5 area centered at the square he is currently in.   In either case, he cannot go out of the maze.  At least how many times does he need to use the magic to reach (D_h, D_w) ?      Constraints  1 \leq H,W \leq 10^3  1 \leq C_h,D_h \leq H  1 \leq C_w,D_w \leq W  S_{ij} is # or . .  S_{C_h C_w} and S_{D_h D_w} are . .  (C_h,C_w) \neq (D_h,D_w)         Input Input is given from Standard Input in the following format:  H  W  C_h  C_w  D_h  D_w  S_{11}\ldots S_{1W}  \vdots  S_{H1}\ldots S_{HW}       Output Print the minimum number of times the magician needs to use the magic. If he cannot reach (D_h,D_w) , print -1 instead.        Sample Input 1 4 4
1 1
4 4
..#.
..#.
.#..
.#..      Sample Output 1 1  For example, by walking to (2,2) and then using the magic to travel to (4,4) , just one use of magic is enough.  Note that he cannot walk diagonally.       Sample Input 2 4 4
1 4
4 1
.##.
####
####
.##.      Sample Output 2 -1  He cannot move from there.       Sample Input 3 4 4
2 2
3 3
....
....
....
....      Sample Output 3 0  No use of magic is needed.       Sample Input 4 4 5
1 2
2 5
#.###
####.
#..##
#..##      Sample Output 4 2

Solution (Python):
from collections import deque
from itertools import product


def bfs(x, y):
    dist = [[10 ** 9] * w for _ in range(h)]
    dist[y][x] = 0
    que = deque([(x, y)])

    while len(que) > 0:
        x, y = que.popleft()
        num = product([-2, -1, 0, 1, 2], repeat=2)
        near = [(x + dx, y + dy) for dx, dy in num]
        if (x, y) == (Dw - 1, Dh - 1):
            return dist[y][x]

        for i, j in near:
            cnt = (abs(x - i) + abs(y - j) >= 2)
            if (0 <= i < w and 0 <= j < h and
                    dist[j][i] > dist[y][x] + cnt and s[j][i] == '.'):
                dist[j][i] = dist[y][x] + cnt
                if cnt == 0:
                    que.appendleft((i, j))
                elif cnt == 1:
                    que.append((i, j))
    return -1


h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
s = [input() for _ in range(h)]

print(bfs(Cw - 1, Ch - 1))

Solution (Python):
import sys,bisect,string,math,time,functools,random,fractions
from heapq import heappush,heappop,heapify
from collections import deque,defaultdict,Counter
from itertools import permutations,combinations,groupby
rep=range;R=range
def Golf():n,*t=map(int,open(0).read().split())
def I():return int(input())
def S_():return input()
def IS():return input().split()
def LS():return [i for i in input().split()]
def MI():return map(int,input().split())
def LI():return [int(i) for i in input().split()]
def LI_():return [int(i)-1 for i in input().split()]
def NI(n):return [int(input()) for i in range(n)]
def NI_(n):return [int(input())-1 for i in range(n)]
def StoLI():return [ord(i)-97 for i in input()]
def ItoS(n):return chr(n+97)
def LtoS(ls):return ''.join([chr(i+97) for i in ls])
def RA():return map(int,open(0).read().split())
def RLI(n=8,a=1,b=10):return [random.randint(a,b)for i in range(n)]
def RI(a=1,b=10):return random.randint(a,b)
def Rtest(T):
    case,err=0,0
    for i in range(T):
        inp=INP()
        a1,ls=naive(*inp)
        a2=solve(*inp)
        if a1!=a2:
            print((a1,a2),inp)
            err+=1
        case+=1
    print('Tested',case,'case with',err,'errors')
def GI(V,E,ls=None,Directed=False,index=1):
    org_inp=[];g=[[] for i in range(V)]
    FromStdin=True if ls==None else False
    for i in range(E):
        if FromStdin:
            inp=LI()
            org_inp.append(inp)
        else:
            inp=ls[i]
        if len(inp)==2:
            a,b=inp;c=1
        else:
            a,b,c=inp
        if index==1:a-=1;b-=1
        aa=(a,c);bb=(b,c);g[a].append(bb)
        if not Directed:g[b].append(aa)
    return g,org_inp
def GGI(h,w,search=None,replacement_of_found='.',mp_def={'
    
    mp=[boundary]*(w+2);found={}
    for i in R(h):
        s=input()
        for char in search:
            if char in s:
                found[char]=((i+1)*(w+2)+s.index(char)+1)
                mp_def[char]=mp_def[replacement_of_found]
        mp+=[boundary]+[mp_def[j] for j in s]+[boundary]
    mp+=[boundary]*(w+2)
    return h+2,w+2,mp,found
def TI(n):return GI(n,n-1)
def accum(ls):
    rt=[0]
    for i in ls:rt+=[rt[-1]+i]
    return rt
def bit_combination(n,base=2):
    rt=[]
    for tb in R(base**n):s=[tb//(base**bt)%base for bt in R(n)];rt+=[s]
    return rt
def gcd(x,y):
    if y==0:return x
    if x%y==0:return y
    while x%y!=0:x,y=y,x%y
    return y
def YN(x):print(['NO','YES'][x])
def Yn(x):print(['No','Yes'][x])
def show(*inp,end='\n'):
    if show_flg:print(*inp,end=end)

mo=10**9+7
inf=float('inf')
FourNb=[(-1,0),(1,0),(0,1),(0,-1)];EightNb=[(-1,0),(1,0),(0,1),(0,-1),(1,1),(-1,-1),(1,-1),(-1,1)];compas=dict(zip('WENS',FourNb));cursol=dict(zip('LRUD',FourNb))
l_alp=string.ascii_lowercase

read=sys.stdin.buffer.read;readline=sys.stdin.buffer.readline;input=lambda:sys.stdin.readline().rstrip()













class Bit: 
    def __init__(self,n,init=None):
        self.size=n
        self.m=len(bin(self.size))-2
        self.arr=[0]*(2**self.m+1)
        self.el=[0]*(2**self.m+1)
        if init!=None:
            for i in range(len(init)):
                self.add(i,init[i])
                self.el[i]=init[i]

    def __str__(self):
        a=[self.sum(i+1)-self.sum(i) for i in range(self.size)]
        return str(a)
        
    def add(self,i,x):
        if not 0<i<=self.size:return NotImplemented
        self.el[i]+=x
        while i<=self.size:
            self.arr[i]+=x
            i+=i&(-i)
        return
    
    def sum(self,i):
        if not 0<=i<=self.size:return NotImplemented
        rt=0
        while i>0:
            rt+=self.arr[i]
            i-=i&(-i)
        return rt
    
    def __getitem__(self,key):
        return self.el[key]
        return self.sum(key+1)-self.sum(key)

    def __setitem__(self,key,value):
        self.add(key,value-self.sum(key+1)+self.sum(key))

    def l_bound(self,w):
        if w<=0:
            return 0
        x=0
        k=2**self.m
        while k>0:
            if x+k<=self.size and self.arr[x+k]<w:
                w-=self.arr[x+k]
                x+=k
            k>>=1
        return x+1
        
    def u_bound(self,w):
        if w<=0:
            return 0
        x=0
        k=2**self.m
        while k>0:
            if x+k<=self.size and self.arr[x+k]<=w:
                w-=self.arr[x+k]
                x+=k
            k>>=1
        return x+1
        
class Bit0(Bit): 
    def add(self,j,x):
        super().add(j+1,x)
    def l_bound(self,w):
        return max(super().l_bound(w)-1,0)
    def u_bound(self,w):
        return max(super().u_bound(w)-1,0)

class Multiset(Bit0):
    def __init__(self,max_v):
        super().__init__(max_v)
    def insert(self,x):
        super().add(x,1)
    def find(self,x):
        return super().l_bound(super().sum(x))
    def __str__(self):
        return str(self.arr)

def compress(L):
    dc={v:i for i,v in enumerate(sorted(set(L)))}
    return [dc[i] for i in L]


show_flg=False
show_flg=True

ans=0

h,w=LI()
sh,sw=LI()
gh,gw=LI()

w+=2
m=[1]*w
for i in range(h):
    s=input()
    m+=[1]+[i=='
m+=[1]*w
h+=2
n=h*w
v=[-1]*w*h

dc=dict()
cn=0
def bfs(x):
    global cn
    q=[x]
    v[x]=x
    dc[x]=cn
    cn+=1
    while q:
        c=q.pop()
        for nx in [c+1,c-1,c+w,c-w]:
            if 0<=nx<n and m[nx]!=1 and v[nx]==-1:
                q+=nx,
                v[nx]=x
    return        
            
for i in range(n):
    if m[i]!=1 and v[i]==-1:
        bfs(i)

g=[set()for i in range(cn)]
nbw=[-2*w+1,-2*w+2,-w+1,-w+2,2,2*w+1,2*w+2,w+1,w+2,+2*w,-2*w,-2*w-1,-2*w-2,-w-1,-w-2,-2,2*w-1,2*w-2,w-1,w-2]
nb=[1,-1,w,-w]
d=[-1]*n
v=[0]*n
vw=[0]*n
q=deque([sh*w+sw])
d[sh*w+sw]=0
vw[sh*w+sw]=1
while q:
    i=q.pop()
    if m[i]==1:
        continue
    for di in nb:
        nx=i+di
        if 0<=nx<n and m[nx]!=1 and (d[nx]==-1 or d[nx]>d[i]):
            d[nx]=d[i]
            q.append(nx)

    for di in nbw:
        nx=i+di
        if 0<=nx<n and m[nx]!=1 and d[nx]==-1:
            q.appendleft(nx)
            d[nx]=d[i]+1
print(d[gh*w+gw])

Solution (Python):
from collections import deque
from itertools import product


def bfs(x, y):
    dist = [[10 ** 9] * w for _ in range(h)]
    dist[y][x] = 0
    que = deque([(x, y)])

    while len(que) > 0:
        x, y = que.popleft()
        near_a = [(x + 1, y), (x - 1, y), (x, y + 1), (x, y - 1)]
        num = product([-2, -1, 0, 1, 2], repeat=2)
        near_b = [(x + dx, y + dy) for dx, dy in num]
        if (x, y) == (Dw - 1, Dh - 1):
            return dist[y][x]

        for cnt, l in enumerate((near_a, near_b)):
            for i, j in l:
                if (0 <= i < w and 0 <= j < h and
                        dist[j][i] > dist[y][x] + cnt and s[j][i] == '.'):
                    dist[j][i] = dist[y][x] + cnt
                    if cnt == 0:
                        que.appendleft((i, j))
                    elif cnt == 1:
                        que.append((i, j))
    return -1


h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
s = [input() for _ in range(h)]

print(bfs(Cw - 1, Ch - 1))

Solution (Python):
import sys,bisect,string,math,time,functools,random,fractions
from heapq import heappush,heappop,heapify
from collections import deque,defaultdict,Counter
from itertools import permutations,combinations,groupby
rep=range;R=range
def Golf():n,*t=map(int,open(0).read().split())
def I():return int(input())
def S_():return input()
def IS():return input().split()
def LS():return [i for i in input().split()]
def MI():return map(int,input().split())
def LI():return [int(i) for i in input().split()]
def LI_():return [int(i)-1 for i in input().split()]
def NI(n):return [int(input()) for i in range(n)]
def NI_(n):return [int(input())-1 for i in range(n)]
def StoLI():return [ord(i)-97 for i in input()]
def ItoS(n):return chr(n+97)
def LtoS(ls):return ''.join([chr(i+97) for i in ls])
def RA():return map(int,open(0).read().split())
def RLI(n=8,a=1,b=10):return [random.randint(a,b)for i in range(n)]
def RI(a=1,b=10):return random.randint(a,b)
def Rtest(T):
    case,err=0,0
    for i in range(T):
        inp=INP()
        a1,ls=naive(*inp)
        a2=solve(*inp)
        if a1!=a2:
            print((a1,a2),inp)
            err+=1
        case+=1
    print('Tested',case,'case with',err,'errors')
def GI(V,E,ls=None,Directed=False,index=1):
    org_inp=[];g=[[] for i in range(V)]
    FromStdin=True if ls==None else False
    for i in range(E):
        if FromStdin:
            inp=LI()
            org_inp.append(inp)
        else:
            inp=ls[i]
        if len(inp)==2:
            a,b=inp;c=1
        else:
            a,b,c=inp
        if index==1:a-=1;b-=1
        aa=(a,c);bb=(b,c);g[a].append(bb)
        if not Directed:g[b].append(aa)
    return g,org_inp
def GGI(h,w,search=None,replacement_of_found='.',mp_def={'
    
    mp=[boundary]*(w+2);found={}
    for i in R(h):
        s=input()
        for char in search:
            if char in s:
                found[char]=((i+1)*(w+2)+s.index(char)+1)
                mp_def[char]=mp_def[replacement_of_found]
        mp+=[boundary]+[mp_def[j] for j in s]+[boundary]
    mp+=[boundary]*(w+2)
    return h+2,w+2,mp,found
def TI(n):return GI(n,n-1)
def accum(ls):
    rt=[0]
    for i in ls:rt+=[rt[-1]+i]
    return rt
def bit_combination(n,base=2):
    rt=[]
    for tb in R(base**n):s=[tb//(base**bt)%base for bt in R(n)];rt+=[s]
    return rt
def gcd(x,y):
    if y==0:return x
    if x%y==0:return y
    while x%y!=0:x,y=y,x%y
    return y
def YN(x):print(['NO','YES'][x])
def Yn(x):print(['No','Yes'][x])
def show(*inp,end='\n'):
    if show_flg:print(*inp,end=end)

mo=10**9+7
inf=float('inf')
FourNb=[(-1,0),(1,0),(0,1),(0,-1)];EightNb=[(-1,0),(1,0),(0,1),(0,-1),(1,1),(-1,-1),(1,-1),(-1,1)];compas=dict(zip('WENS',FourNb));cursol=dict(zip('LRUD',FourNb))
l_alp=string.ascii_lowercase

read=sys.stdin.buffer.read;readline=sys.stdin.buffer.readline;input=lambda:sys.stdin.readline().rstrip()













class Bit: 
    def __init__(self,n,init=None):
        self.size=n
        self.m=len(bin(self.size))-2
        self.arr=[0]*(2**self.m+1)
        self.el=[0]*(2**self.m+1)
        if init!=None:
            for i in range(len(init)):
                self.add(i,init[i])
                self.el[i]=init[i]

    def __str__(self):
        a=[self.sum(i+1)-self.sum(i) for i in range(self.size)]
        return str(a)
        
    def add(self,i,x):
        if not 0<i<=self.size:return NotImplemented
        self.el[i]+=x
        while i<=self.size:
            self.arr[i]+=x
            i+=i&(-i)
        return
    
    def sum(self,i):
        if not 0<=i<=self.size:return NotImplemented
        rt=0
        while i>0:
            rt+=self.arr[i]
            i-=i&(-i)
        return rt
    
    def __getitem__(self,key):
        return self.el[key]
        return self.sum(key+1)-self.sum(key)

    def __setitem__(self,key,value):
        self.add(key,value-self.sum(key+1)+self.sum(key))

    def l_bound(self,w):
        if w<=0:
            return 0
        x=0
        k=2**self.m
        while k>0:
            if x+k<=self.size and self.arr[x+k]<w:
                w-=self.arr[x+k]
                x+=k
            k>>=1
        return x+1
        
    def u_bound(self,w):
        if w<=0:
            return 0
        x=0
        k=2**self.m
        while k>0:
            if x+k<=self.size and self.arr[x+k]<=w:
                w-=self.arr[x+k]
                x+=k
            k>>=1
        return x+1
        
class Bit0(Bit): 
    def add(self,j,x):
        super().add(j+1,x)
    def l_bound(self,w):
        return max(super().l_bound(w)-1,0)
    def u_bound(self,w):
        return max(super().u_bound(w)-1,0)

class Multiset(Bit0):
    def __init__(self,max_v):
        super().__init__(max_v)
    def insert(self,x):
        super().add(x,1)
    def find(self,x):
        return super().l_bound(super().sum(x))
    def __str__(self):
        return str(self.arr)

def compress(L):
    dc={v:i for i,v in enumerate(sorted(set(L)))}
    return [dc[i] for i in L]


show_flg=False
show_flg=True

ans=0

h,w=LI()
sh,sw=LI()
gh,gw=LI()

w+=2
m=[1]*w
for i in range(h):
    s=input()
    m+=[1]+[i=='
m+=[1]*w
h+=2
n=h*w
v=[-1]*w*h

dc=dict()
cn=0
def bfs(x):
    global cn
    q=[x]
    v[x]=x
    dc[x]=cn
    cn+=1
    while q:
        c=q.pop()
        for nx in [c+1,c-1,c+w,c-w]:
            if 0<=nx<n and m[nx]!=1 and v[nx]==-1:
                q+=nx,
                v[nx]=x
    return        
            
for i in range(n):
    if m[i]!=1 and v[i]==-1:
        bfs(i)

g=[set()for i in range(cn)]
nbw=[-2*w+1,-2*w+2,-w+1,-w+2,2,2*w+1,2*w+2,w+1,w+2,+2*w,-2*w,-2*w-1,-2*w-2,-w-1,-w-2,-2,2*w-1,2*w-2,w-1,w-2]
nb=[1,-1,w,-w]
d=[-1]*n
v=[0]*n
vw=[0]*n
q=deque([(sh*w+sw,0)])
v[sh*w+sw]=1
vw[sh*w+sw]=1
while q:
    i,dist=q.pop()
    if d[i]==-1:
        d[i]=dist
    else:
        d[i]=min(dist,d[i])
    if m[i]==1:
        continue
    for di in nb:
        nx=i+di
        if 0<=nx<n and m[nx]!=1 and v[nx]==0:
            
            v[nx]=1
            q.append((nx,d[i]))

    for di in nbw:
        nx=i+di
        if 0<=nx<n and m[nx]!=1 and vw[nx]==0:
            vw[nx]=1
            q.appendleft((nx,d[i]+1))
print(d[gh*w+gw])

Solution (Python):
from collections import deque
from itertools import product


def bfs(x, y):
    dist = [[10 ** 9] * w for _ in range(h)]
    dist[y][x] = 0
    for i, si in enumerate(s):
        for j, sij in enumerate(si):
            if sij == '
                dist[i][j] = -1
    que = deque([(x, y)])

    while len(que) > 0:
        x, y = que.popleft()
        near_a = [(x + 1, y), (x - 1, y), (x, y + 1), (x, y - 1)]
        num = product([-2, -1, 0, 1, 2], repeat=2)
        near_b = [(x + dx, y + dy) for dx, dy in num]

        for cnt, l in enumerate((near_a, near_b)):
            for i, j in l:
                if (0 <= i < w and 0 <= j < h and
                        dist[j][i] > dist[y][x] + cnt and s[j][i] == '.'):
                    dist[j][i] = dist[y][x] + cnt
                    if cnt == 0:
                        que.appendleft((i, j))
                    elif cnt == 1:
                        que.append((i, j))
    return dist


h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
s = [input() for _ in range(h)]

ans = bfs(Cw - 1, Ch - 1)[Dh - 1][Dw - 1]
print(-1 if ans == 10 ** 9 else ans)

Solution (Python):

from collections import deque
H, W = map(int, input().split())
Ch, Cw = map(lambda x:int(x)-1, input().split())
Dh, Dw = map(lambda x:int(x)-1, input().split())
meiro = []
for i in range(H):
    meiro.append(list(map(str, input())))
    
walk = [(0,1),(1,0),(0,-1),(-1,0)]
warp = [(i,j) for i in range(-2,3) for j in range(-2,3) if (i,j) not in [(0,0)]+walk]

q = deque()
q.append((Ch,Cw))
num = 0
meiro[Ch][Cw] = num


while q != deque():

    ph, pw = q.popleft()
    
    if meiro[ph][pw] != num:
        num += 1
    
    for h, w in walk:
        th = ph+h
        tw = pw+w
        
        if 0 <= th < H and 0 <= tw < W and meiro[th][tw] != '
            meiro[th][tw] = meiro[ph][pw]
            q.appendleft((th,tw))
    
    for h, w in warp:
        th = ph+h
        tw = pw+w
        
        if 0 <= th < H and 0 <= tw < W and meiro[th][tw] == '.':
            meiro[th][tw] = meiro[ph][pw] + 1
            q.append((th,tw))
    
if meiro[Dh][Dw] == '.':
    print(-1)
else:
    print(meiro[Dh][Dw])

Solution (Python):
from collections import deque

H, W = map(int, input().split())
sy, sx = map(lambda x: int(x)-1, input().split())
gy, gx = map(lambda x: int(x)-1, input().split())
maze = [input() for _ in range(H)]

INF = float("INF")
cnt = [[INF]*W for _ in range(H)]

q = deque()
q.append([sy, sx])
cnt[sy][sx] = 0
move = [[1, 0], [-1, 0], [0, 1], [0, -1]]

while q:
    y, x = q.popleft()
    for dy, dx in move:
        ny = y + dy
        nx = x + dx
        if ny < 0 or ny > H-1 or nx < 0 or nx > W-1:
            continue
        if maze[ny][nx] == "." and cnt[ny][nx] > cnt[y][x]:
            cnt[ny][nx] = cnt[y][x]
            q.appendleft([ny, nx])
    for i in range(-2, 2+1):
        for j in range(-2, 2+1):
            wy = y + i
            wx = x + j
            if wy < 0 or wy > H-1 or wx < 0 or wx > W-1:
                continue
            if maze[wy][wx] == "." and cnt[wy][wx] > cnt[y][x] + 1:
                cnt[wy][wx] = cnt[y][x] + 1
                q.append([wy, wx])

ans = cnt[gy][gx] if cnt[gy][gx] != INF else -1
print(ans)

Solution (Python):
from collections import deque

H, W = map(int, input().split())
sy, sx = map(lambda x: int(x)-1, input().split())
gy, gx = map(lambda x: int(x)-1, input().split())
maze = [input() for _ in range(H)]

INF = float("INF")
cnt = [[INF]*W for _ in range(H)]

q = deque()
q.append([sy, sx])
cnt[sy][sx] = 0
move = [[1, 0], [-1, 0], [0, 1], [0, -1]]

while q:
    y, x = q.popleft()
    for dy, dx in move:
        ny = y + dy
        nx = x + dx
        if ny < 0 or ny > H-1 or nx < 0 or nx > W-1:
            continue
        if maze[ny][nx] == "." and cnt[ny][nx] > cnt[y][x]:
            cnt[ny][nx] = cnt[y][x]
            q.appendleft([ny, nx])
        for i in range(-2, 2+1):
            for j in range(-2, 2+1):
                wy = y + i
                wx = x + j
                if wy < 0 or wy > H-1 or wx < 0 or wx > W-1:
                    continue
                if maze[wy][wx] == "." and cnt[wy][wx] > cnt[y][x] + 1:
                    cnt[wy][wx] = cnt[y][x] + 1
                    q.append([wy, wx])

ans = cnt[gy][gx] if cnt[gy][gx] != INF else -1
print(ans)

Solution (Python):
from collections import deque
from itertools import product


def bfs(x, y):
    dist = [[10 ** 9] * w for _ in range(h)]
    dist[y][x] = 0
    que = deque([(x,y)])

    while len(que) > 0:
        x, y = que.popleft()
        near_a = [(x + 1, y), (x - 1, y), (x, y + 1), (x, y - 1)]
        num = product([-2, -1, 0, 1, 2], repeat=2)
        near_b = [(x + dx, y + dy) for dx, dy in num]

        for cnt, l in enumerate((near_a, near_b)):
            for i, j in l:
                if (0 <= i < w and 0 <= j < h and
                        dist[j][i] > dist[y][x] + cnt and s[j][i] == '.'):
                    dist[j][i] = dist[y][x] + cnt
                    if cnt == 0:
                        que.appendleft((i, j))
                    elif cnt == 1:
                        que.append((i, j))
    return dist


h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
s = [input() for _ in range(h)]

ans = bfs(Cw - 1, Ch - 1)[Dh - 1][Dw - 1]
print(-1 if ans == 10 ** 9 else ans)

Solution (Python):
from collections import deque
from itertools import product


def bfs(S):
    x, y = S
    dist = [[10 ** 9] * w for _ in range(h)]
    dist[y][x] = 0
    que = deque([S])

    while len(que) > 0:
        x, y = que.popleft()
        near_a = [(x + 1, y), (x - 1, y), (x, y + 1), (x, y - 1)]
        num = product([-2, -1, 0, 1, 2], repeat=2)
        near_b = [(x + dx, y + dy) for dx, dy in num]

        for i, j in near_a:
            if (0 <= i < w and 0 <= j < h and
                    dist[j][i] > dist[y][x] and s[j][i] == '.'):
                dist[j][i] = dist[y][x]
                que.appendleft((i, j))
        for i, j in near_b:
            if (0 <= i < w and 0 <= j < h and
                    dist[j][i] > dist[y][x] + 1 and s[j][i] == '.'):
                dist[j][i] = dist[y][x] + 1
                que.append((i, j))
    return dist


h, w = map(int, input().split())
Ch, Cw = map(int, input().split())
Dh, Dw = map(int, input().split())
s = [input() for _ in range(h)]

ans = bfs((Cw - 1, Ch - 1))[Dh - 1][Dw - 1]
print(-1 if ans == 10 ** 9 else ans)

Solution (Python):
from collections import deque


def solve(H, W, Ch, Cw, Dh, Dw, maze):
    
    walled_maze = ['
    walled_maze.insert(0, '
    walled_maze.insert(0, '
    walled_maze.append('
    walled_maze.append('

    INF = 10 ** 12
    path = [[INF] * (W + 4) for _ in range(H + 4)]
    walk = [(0, 1), (0, -1), (-1, 0), (1, 0)]
    warp = [(i, j) for i in range(-2, 3) for j in range(-2, 3) if (i, j) not in [(0, 0)] + walk]

    yet = deque()
    yet.append((Ch + 2, Cw + 2, 0))    
    path[Ch + 2][Cw + 2] = 0
    done = deque()

    while yet:
        y, x, s = yet.popleft()
        done.append((y, x, s))
        for dy, dx in walk:
            ny = y + dy
            nx = x + dx
            if walled_maze[ny][nx] == '.' and path[ny][nx] > s:
                path[ny][nx] = s
                yet.append((ny, nx, s))
        if len(yet) == 0:
            while done:
                y, x, s = done.popleft()
                for dy, dx in warp:
                    ny = y + dy
                    nx = x + dx
                    if walled_maze[ny][nx] == '.' and path[ny][nx] > s + 1:
                        path[ny][nx] = s + 1
                        yet.append((ny, nx, s + 1))
    ans = path[Dh + 2][Dw + 2] if path[Dh + 2][Dw + 2] < INF else -1
    print(ans)


if __name__ == '__main__':
    H, W = map(int, input().split())
    Ch, Cw = map(lambda x: int(x) - 1, input().split())
    Dh, Dw = map(lambda x: int(x) - 1, input().split())
    maze = [input() for _ in range(H)]
    solve(H, W, Ch, Cw, Dh, Dw, maze)

Solution (Python):



from queue import deque

def main():
  h, w = map(int, input().strip().split())
  c_h, c_w = map(int, input().strip().split())
  d_h, d_w = map(int, input().strip().split())
  maze = [list(input().strip()) for _ in range(h)]
  visited = [[0] * w for _ in range(h)]
  
  def bfs():
    dq = deque([(c_h-1, c_w-1, 0)])
    while dq:
      (ih, iw, cnt) = dq.pop()
      if visited[ih][iw]:
        continue
      visited[ih][iw] = 1
      
      if ih == d_h-1 and iw == d_w-1:
        return cnt
      
      for dh in range(-2, 3):
        for dw in range(-2, 3):
          if not (0 <= ih + dh < h and 0 <= iw + dw < w) \
             or visited[ih + dh][iw + dw] == 1 \
             or maze[ih + dh][iw + dw] == '
            continue
          if (dh, dw) in [(0, 1), (0, -1), (1, 0), (-1, 0)]:
            dq.append((ih + dh, iw + dw, cnt))
          else:
            dq.appendleft((ih + dh, iw + dw, cnt+1))
      
    return -1
  print(bfs())
  
if __name__=='__main__':
  main()

Solution (Python):
from collections import deque

h, w = map(int, input().split())
sx, sy = map(int, input().split())
gx, gy = map(int, input().split())
M = [[] for _ in range(h)]
for i in range(h):
    M[i] = input()

D = [(-1, 0), (0, -1), (1, 0), (0, 1)]
dist = [[float("inf")] * w for _ in range(h)]
dist[sx - 1][sy - 1] = 0
q = deque()
q.append((sx - 1, sy - 1))
while q:
    X, Y = q.popleft()
    d = dist[X][Y]
    for dx, dy in D:
        nx, ny = X + dx, Y + dy
        if nx < 0 or ny < 0 or nx >= h or ny >= w:
            continue
        if M[nx][ny] == "
            continue
        if dist[nx][ny] <= d:
            continue
        dist[nx][ny] = d
        q.appendleft((nx, ny))
    for c in range(-2, 3):
        for r in range(-2, 3):
            nx, ny = X + c, Y + r
            if nx < 0 or ny < 0 or nx >= h or ny >= w:
                continue
            if M[nx][ny] == "
                continue
            if dist[nx][ny] <= d + 1:
                continue
            dist[nx][ny] = d + 1
            q.append((nx, ny))

ans = dist[gx - 1][gy - 1]
if ans == float("inf"):
    ans = -1

print(ans)

Solution (Python):
import bisect, collections, copy, heapq, itertools, math, string
import sys
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())


def main():
    from collections import deque
    H, W = MI()
    C = LI()
    D = LI()
    C = [i - 1 for i in C]
    D = [i - 1 for i in D]
    S_ = []
    for i in range(H):
        s = S()
        S_.append(s)
    cost = [[10 ** 10] * W for _ in range(H)]
    cost[C[0]][C[1]] = 0
    queue = deque()
    queue.append(C)
    while len(queue) != 0:
        a = queue.popleft()
        a_cost = cost[a[0]][a[1]]
        for i in range(-2, 3):
            if a[0] + i < 0 or a[0] + i >= H:
                continue
            for j in range(-2, 3):
                if a[1] + j < 0 or a[1] + j >= W:
                    continue
                if i == j == 0:
                    continue
                b = [a[0] + i, a[1] + j]
                b_cost = cost[b[0]][b[1]]
                if S_[b[0]][b[1]] == '
                    continue
                if (abs(i) == 1 and j == 0) or (abs(j) == 1 and i == 0):
                    if a_cost < b_cost:
                        cost[b[0]][b[1]] = a_cost
                        queue.appendleft(b)
                else:
                    if a_cost + 1 < b_cost:
                        cost[b[0]][b[1]] = a_cost + 1
                        queue.append(b)
    ans = cost[D[0]][D[1]]
    if ans != 10 ** 10:
        print(ans)
    else:
        print(-1)

if __name__ == "__main__":
    main()

Solution (Python):
from collections import deque


H, W = map(int, input().split())
Ch, Cw = map(lambda x:int(x) - 1, input().split())
Dh, Dw = map(lambda x:int(x) - 1, input().split())
S = [list(input()) for _ in range(H)]


dh = [0, 0, 1, -1]
dw = [1, -1, 0, 0]
INF = float('inf')


def main():
    dist = [[INF] * W for i in range(H)]
    que = deque()
    dist[Ch][Cw] = 0
    que.append([Ch, Cw])

    
    while que:
        h, w = que.popleft()
        d = dist[h][w]
        for i in range(4):
            nh = h + dh[i]
            nw = w + dw[i]
            if nh < 0 or nw < 0 or nh >= H or nw >= W:
                continue
            if S[nh][nw] == '
                continue
            if dist[nh][nw] <= d:
                continue
            dist[nh][nw] = d
            que.appendleft([nh, nw])
        
        
        for mh in range(-2, 3):
            for mw in range(-2, 3):
                nh = h + mh
                nw = w + mw
                if nh < 0 or nw < 0 or nh >= H or nw >= W:
                    continue
                if S[nh][nw] == '
                    continue
                if dist[nh][nw] <= d + 1:
                    continue
                dist[nh][nw] = d + 1
                que.append([nh, nw])
    
    ans = dist[Dh][Dw]
    if ans == INF:
        ans = -1
    print(ans)


if __name__ == "__main__":
    main()

Solution (Python):
def resolve():
    '''
    code here
    '''
    from collections import deque

    H, W = [int(item) for item in input().split()]
    Ch, Cw = [int(item)-1 for item in input().split()]
    Dh, Dw = [int(item)-1 for item in input().split()]
    grid = [input() for _ in range(H)]
    max_num = 10**6
    fp = [[max_num] * W for _ in range(H)]

    que = deque([[Ch, Cw, 0]])
    fp[Ch][Cw] = 0

    walk = [(0, 1), (0, -1), (-1, 0), (1, 0)]
    warp = [(i, j) for i in range(-2, 3) for j in range(-2, 3) if (i, j) not in [(0, 0)] + walk]

    while que:
        y, x, w_num = que.popleft()

        for dy, dx in walk:
            ny = y + dy
            nx = x + dx

            if 0 <= ny <= H-1 and 0 <= nx <= W-1 and grid[ny][nx] == '.' and fp[ny][nx] > w_num:
                que.appendleft([ny, nx, w_num])
                fp[ny][nx] = w_num

        for dy, dx in warp:
            ny = y + dy
            nx = x + dx
            nw = w_num +1

            if 0 <= ny <= H-1 and 0 <= nx <= W-1 and grid[ny][nx] == '.' and fp[ny][nx] > nw:
                que.append([ny, nx, nw])
                fp[ny][nx] = nw

    if fp[Dh][Dw] != max_num:
        print(fp[Dh][Dw])
    else:
        print(-1)

if __name__ == "__main__":
    resolve()

Solution (Python):
import sys
from collections import deque


input = lambda: sys.stdin.readline().rstrip()


if __name__ == "__main__":
    H, W = map(int, input().split())
    ch, cw = map(lambda x: int(x)+1, input().split())
    dh, dw = map(lambda x: int(x)+1, input().split())
    maze = ["
    maze += [list("
    maze += ["
    INF = 10**8
    mc = [[INF]*(W+4) for _ in range(H+4)]
    mc[ch][cw] = 0
    walk = [(1, 0), (0, 1), (-1, 0), (0, -1)]
    warp = [(y, x) for x in range(-2, 3) for y in range(-2, 3) if abs(y) + abs(x) > 1]
    que = deque()
    que.append((ch, cw, 0))
    while que:
        y, x, w = que.popleft()
        if mc[y][x] < w:
            continue
        for dy, dx in walk:
            ny = y + dy
            nx = x + dx
            if maze[ny][nx] == "." and mc[ny][nx] > w:
                mc[ny][nx] = w
                que.appendleft((ny, nx, w))
        for dy, dx in warp:
            ny = y + dy
            nx = x + dx
            if maze[ny][nx] == "." and mc[ny][nx] > w+1:
                mc[ny][nx] = w+1
                que.append((ny, nx, w+1))
    if mc[dh][dw] == INF:
        print(-1)
    else:
        print(mc[dh][dw])