Problem:


Score : 400 points

Problem Statement

Takahashi has a maze, which is a grid of H \times W squares with H horizontal rows and W vertical columns.

The square at the i-th row from the top and the j-th column is a "wall" square if S_{ij} is #, and a "road" square if S_{ij} is ..

From a road square, you can move to a horizontally or vertically adjacent road square.

You cannot move out of the maze, move to a wall square, or move diagonally.

Takahashi will choose a starting square and a goal square, which can be any road squares, and give the maze to Aoki.

Aoki will then travel from the starting square to the goal square, in the minimum number of moves required.

In this situation, find the maximum possible number of moves Aoki has to make.

Constraints

1 \leq H,W \leq 20

S_{ij} is . or #.

S contains at least two occurrences of ..

Any road square can be reached from any road square in zero or more moves.

Input

Input is given from Standard Input in the following format:

H W
S_{11}...S_{1W}
:
S_{H1}...S_{HW}

Output

Print the maximum possible number of moves Aoki has to make.

Sample Input 1

3 3
...
...
...

Sample Output 1

4

If Takahashi chooses the top-left square as the starting square and the bottom-right square as the goal square, Aoki has to make four moves.

Sample Input 2

3 5
...#.
.#.#.
.#...

Sample Output 2

10

If Takahashi chooses the bottom-left square as the starting square and the top-right square as the goal square, Aoki has to make ten moves.



Sample input:
3 3
...
...
...


Sample output:
4

Submission status: Runtime Error

Solution code:
from copy import deepcopy
from collections import deque
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)

M = []
vx = [0,1,0,-1]
vy = [1,0,-1,0]
H = 0
W = 0
qx = deque()
qy = deque()
qc = deque()

def main():
    global M,H,W
    H,W = map(int, input().split())  
    for i in range(H):
        M.append(list(input()))

    startX = 0
    startY = 0
    for i in range(H):
        startX = M[i].index('.')
        if startX >= 0:
            startY = i
            break

    Mtemp = deepcopy(M)

    Mtemp[startY][startX] = '#'
    qx.append(startX)
    qy.append(startY)
    qc.append(0)
    cnt = 0
    x = 0 
    y = 0

    while len(qx) !=0:
        x =  qx.popleft()
        y =  qy.popleft()
        cnt = qc.popleft()

        if x-1>=0:
            if Mtemp[y][x-1] == '.':
                Mtemp[y][x-1] = '#'
                qx.append(x-1)
                qy.append(y)
                qc.append(cnt+1)
        if x+1<W:
            if Mtemp[y][x+1] == '.':
                Mtemp[y][x+1] = '#'
                qx.append(x+1)
                qy.append(y)
                qc.append(cnt+1)
        if y-1>=0:
            if Mtemp[y-1][x] == '.':
                Mtemp[y-1][x] = '#'
                qx.append(x)
                qy.append(y-1)
                qc.append(cnt+1)
        if y+1<H:
            if Mtemp[y+1][x] == '.':
                Mtemp[y+1][x] = '#'
                qx.append(x)
                qy.append(y+1)
                qc.append(cnt+1)

    Mtemp = deepcopy(M)

    Mtemp[y][x] = '#'
    qx.append(x)
    qy.append(y)
    qc.append(0)

    while len(qx) !=0:
        x =  qx.popleft()
        y =  qy.popleft()
        cnt = qc.popleft()

        if x-1>=0:
            if Mtemp[y][x-1] == '.':
                Mtemp[y][x-1] = '#'
                qx.append(x-1)
                qy.append(y)
                qc.append(cnt+1)
        if x+1<W:
            if Mtemp[y][x+1] == '.':
                Mtemp[y][x+1] = '#'
                qx.append(x+1)
                qy.append(y)
                qc.append(cnt+1)
        if y-1>=0:
            if Mtemp[y-1][x] == '.':
                Mtemp[y-1][x] = '#'
                qx.append(x)
                qy.append(y-1)
                qc.append(cnt+1)
        if y+1<H:
            if Mtemp[y+1][x] == '.':
                Mtemp[y+1][x] = '#'
                qx.append(x)
                qy.append(y+1)
                qc.append(cnt+1)


    print(cnt)




if __name__ == '__main__':
    main()

Submission status: Runtime Error

Solution code:
from copy import deepcopy
from collections import deque
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)

M = []
vx = [0,1,0,-1]
vy = [1,0,-1,0]
H = 0
W = 0
qx = deque()
qy = deque()
qc = deque()

def main():
    global M,H,W
    H,W = map(int, input().split())  
    for i in range(H):
        M.append(list(input()))

    startX = 0
    startY = 0
    for i in range(H):
        startX = M[i].index('.')
        if startX >= 0:
            startY = i
            break

    Mtemp = deepcopy(M)

    Mtemp[startY][startX] = '#'
    qx.append(startX)
    qy.append(startY)
    qc.append(0)
    cnt = 0
    x = 0 
    y = 0

    while len(qx) !=0:
        x =  qx.popleft()
        y =  qy.popleft()
        cnt = qc.popleft()

        if x-1>=0:
            if Mtemp[x-1][y] == '.':
                Mtemp[x-1][y] = '#'
                qx.append(x-1)
                qy.append(y)
                qc.append(cnt+1)
        if x+1<W:
            if Mtemp[x+1][y] == '.':
                Mtemp[x+1][y] = '#'
                qx.append(x+1)
                qy.append(y)
                qc.append(cnt+1)
        if y-1>=0:
            if Mtemp[x][y-1] == '.':
                Mtemp[x][y-1] = '#'
                qx.append(x)
                qy.append(y-1)
                qc.append(cnt+1)
        if y+1<H:
            if Mtemp[x][y+1] == '.':
                Mtemp[x][y+1] = '#'
                qx.append(x)
                qy.append(y+1)
                qc.append(cnt+1)

    Mtemp = deepcopy(M)

    Mtemp[x][y] = '#'
    qx.append(x)
    qy.append(y)
    qc.append(0)

    while len(qx) !=0:
        x =  qx.popleft()
        y =  qy.popleft()
        cnt = qc.popleft()

        if x-1>=0:
            if Mtemp[x-1][y] == '.':
                Mtemp[x-1][y] = '#'
                qx.append(x-1)
                qy.append(y)
                qc.append(cnt+1)
        if x+1<W:
            if Mtemp[x+1][y] == '.':
                Mtemp[x+1][y] = '#'
                qx.append(x+1)
                qy.append(y)
                qc.append(cnt+1)
        if y-1>=0:
            if Mtemp[x][y-1] == '.':
                Mtemp[x][y-1] = '#'
                qx.append(x)
                qy.append(y-1)
                qc.append(cnt+1)
        if y+1<H:
            if Mtemp[x][y+1] == '.':
                Mtemp[x][y+1] = '#'
                qx.append(x)
                qy.append(y+1)
                qc.append(cnt+1)



    print(cnt)




if __name__ == '__main__':
    main()

Submission status: Runtime Error

Solution code:
from copy import deepcopy
from collections import deque
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)

M = []
vx = [0,1,0,-1]
vy = [1,0,-1,0]
H = 0
W = 0
qx = deque()
qy = deque()
qc = deque()

def main():
    global M,H,W
    H,W = map(int, input().split())  
    for i in range(H):
        M.append(list(input()))

    startX = 0
    startY = 0
    for i in range(H):
        startX = M[i].index('.')
        if startX >= 0:
            startY = i
            break

    Mtemp = deepcopy(M)

    Mtemp[startY][startX] = '#'
    qx.append(startX)
    qy.append(startY)
    qc.append(0)
    cnt = 0
    x = 0 
    y = 0

    while len(qx) !=0:
        x =  qx.popleft()
        y =  qy.popleft()
        cnt = qc.popleft()

        if x-1>=0:
            if Mtemp[x-1][y] == '.':
                Mtemp[x-1][y] = '#'
                qx.append(x-1)
                qy.append(y)
                qc.append(cnt+1)
        if x+1<H:
            if Mtemp[x+1][y] == '.':
                Mtemp[x+1][y] = '#'
                qx.append(x+1)
                qy.append(y)
                qc.append(cnt+1)
        if y-1>=0:
            if Mtemp[x][y-1] == '.':
                Mtemp[x][y-1] = '#'
                qx.append(x)
                qy.append(y-1)
                qc.append(cnt+1)
        if y+1<W:
            if Mtemp[x][y+1] == '.':
                Mtemp[x][y+1] = '#'
                qx.append(x)
                qy.append(y+1)
                qc.append(cnt+1)

    Mtemp = deepcopy(M)

    Mtemp[x][y] = '#'
    qx.append(x)
    qy.append(y)
    qc.append(0)

    while len(qx) !=0:
        x =  qx.popleft()
        y =  qy.popleft()
        cnt = qc.popleft()

        if x-1>=0:
            if Mtemp[x-1][y] == '.':
                Mtemp[x-1][y] = '#'
                qx.append(x-1)
                qy.append(y)
                qc.append(cnt+1)
        if x+1<H:
            if Mtemp[x+1][y] == '.':
                Mtemp[x+1][y] = '#'
                qx.append(x+1)
                qy.append(y)
                qc.append(cnt+1)
        if y-1>=0:
            if Mtemp[x][y-1] == '.':
                Mtemp[x][y-1] = '#'
                qx.append(x)
                qy.append(y-1)
                qc.append(cnt+1)
        if y+1<W:
            if Mtemp[x][y+1] == '.':
                Mtemp[x][y+1] = '#'
                qx.append(x)
                qy.append(y+1)
                qc.append(cnt+1)



    print(cnt)




if __name__ == '__main__':
    main()

Submission status: Runtime Error

Solution code:
#関数を持ってくる
from collections import deque

#入力(座標をリストで扱いやすいように-1する)
r,c = map(int,input().split())
c_list = [list(input()) for nesya in range(r)]
for hoge in c_list:
  hoge.insert(0,'#')
  hoge.append('#')
c_list.insert(0,['#']*(c+2))
c_list.append(['#']*(c+2))

ans = 0
for i in range(r+2):
  for j in range(c+2):
    #dequeオブジェクトを作る
    d = deque()
    #その座標を扱ったかを調べるためのリストを作る
    hoge_list = [[-1]*(c+2) for motsu in range(r+2)]
    if  c_list[j][i] == '#':
      continue
    else:
      #スタート位置をdに加え、到達時刻を0にする
      d.append((j,i))
      hoge_list[j][i] = 0

      #当該の座標から動かすためのリストを作る
      move =[[1,0],[-1,0],[0,1],[0,-1]]

      #座標に対して作業する
      while len(d) > 0:
        #今から扱う座標をcoordとする
        coord = d.popleft()
  
        #縦横に移動したときそれぞれのマスに作業する
        for k in range(4):
          #移動した後の座標
          x = coord[1] + move[k][1]
          y = coord[0] + move[k][0]
    
          #作業が終わっている座標であったら無視する
          if hoge_list[y][x] != -1:
            pass
          #マスが壁であった場合-2を代入して終わる
          elif c_list[y][x] == '#':
            hoge_list[y][x] = -2
          #作業するマス
          else:
            #当該座標から1移動したはずである
            hoge_list[y][x] = hoge_list[coord[0]][coord[1]] + 1
            ans = max(hoge_list[y][x],ans)
            #dequeに加える
            d.append((y,x))
    

#ゴールの移動回数を出力する
print(ans)

Submission status: Runtime Error

Solution code:
ii = lambda : int(input())
mi = lambda : map(int,input().split())
li = lambda : list(map(int,input().split()))

h,w = mi()

st = [['#'] * (w+2) for i in range(h+2)]
for i in range(h):
    l = input()
    for j in range(w):
        st[i+1][j+1] = l[j]

ans = 0

from collections import deque
for i in range(1,h+1):
    for j in range(1,w+1):
        if st[i][j] == '.':
            ex = [[0] * (w+2) for i in range(h+2)]
            ex[i][j] = 1

            l = deque()
            l.append((i,j))

            while len(l) != 0:
                x,y = l.popleft()
                step = ex[x][y]
                for xx,yy in [(x-1,y),(x,y-1), (x+1,y),(x,y+1)]:
                    if st[xx][yy] == '.' and ex[xx][yy] == 0:
                        l.append((xx,yy))
                        ex[xx][yy] = step+1

            # for k in range(h+2):
            #     print(ex[k])

            # print('--------------')
        # ans = max(ans, step-1)
        for k in range(1,h+1):
            ans = max(ans,max(ex[k])-1)
print(ans)

Submission status: Runtime Error

Solution code:
ii = lambda : int(input())
mi = lambda : map(int,input().split())
li = lambda : list(map(int,input().split()))

h,w = mi()

st = [['#'] * (w+2) for i in range(h+2)]
for i in range(h):
    l = input()
    for j in range(w):
        st[i+1][j+1] = l[j]


ans = 0

from collections import deque
from itertools import chain
for i in range(1,h+1):
    for j in range(1,w+1):
        if st[i][j] == '.':
            ex = [[0] * (w+2) for i in range(h+2)]
            ex[i][j] = 1

            l = deque()
            l.append((i,j))

            while len(l) != 0:
                x,y = l.popleft()
                step = ex[x][y]
                for xx,yy in [(x-1,y),(x,y-1), (x+1,y),(x,y+1)]:
                    if st[xx][yy] == '.' and ex[xx][yy] == 0:
                        l.append((xx,yy))
                        ex[xx][yy] = step+1
        ans = max(ans, step-1)
print(ans)

Submission status: Runtime Error

Solution code:
from collections import deque

def bfs(maze, sy, sx, gy, gx, H, W):
    """
    maze>>迷路
    visited>>探索済み
    sy, sx>>スタート地点
    gy, gx>>ゴール地点
    """
    queue = deque([[sy, sx]])
    visited = [[-1]*W for _ in range(H)]
    visited[sy][sx] = 0
    while queue:
        y, x = queue.popleft()
        if [y, x] == [gy, gx]:
            return visited[y][x]
        for j, k in ([1, 0], [-1, 0], [0, 1], [0, -1]):
            new_y, new_x = y+j, x+k

            if new_y < 0 or H -1 < new_y or new_x < 0 or W -1 < new_x:
                continue
            elif maze[new_y][new_x] != '#' and visited[new_y][new_x] == -1:
                visited[new_y][new_x] = visited[y][x] + 1
                queue.append([new_y, new_x])


H, W = map(int, input().split())
maze = [list(input()) for _ in range(H)]

answer_list = []
for sy in range(H):
    for sx in range(W):
        if maze[sy][sx] == '#':
            break
        for gy in range(H):
            for gx in range(W):
                if maze[gy][gx] == '#':
                    break
                answer_list.append(bfs(maze, sy, sx, gy, gx, H, W))

print(max(answer_list))

Submission status: Runtime Error

Solution code:
from collections import deque

h, w = map(int, input().split())

maze = [input() for i in range(h)]

ans = 0
INF = 20 * 20 + 1
for j in range(h):
    for i in range(w):
        if maze[j][i] == ".":
            cnt = [[INF] * w for _ in range(h)] 
            cnt[j][i] = 0
            q = deque([(j,i)])
            while q:
                y,x = q.popleft()
                for by,bx in ((0,1),(0,-1),(1,0),(-1,0)):
                    by += y
                    bx += x 
                    if 0 <= by < h and 0 <= bx < w:
                        ct = cnt[y][x] + 1
                        if maze[ny][nx] == "." and ct < cnt[ny][nx]:
                            q += [(by,bx)] 
                            cnt[by][bx] = ct
                            ans = max(ans, cnt[by][bx])

print(ans)

Submission status: Runtime Error

Solution code:
import copy
h,w = map(int,input().split())

s = [['#' for _ in range(w+2)]]
for i in range(h):
    si = ['#']
    sij = list(input())
    si.extend(sij)
    si.append('#')
    s.append(si)
s.append(['#' for _ in range(w+2)])

def bfs(i,j):
    root = copy.deepcopy(s)
    q = []
    q.append([i,j])
    root[i][j] = 0
    while q:
        ij = q.pop(0)
        i = ij[0]
        j = ij[1]
        
        if root[i-1][j] == '.': #左
            q.append([i-1,j])
            root[i-1][j] = root[i][j] + 1
        if root[i+1][j] == '.': #右
            q.append([i+1,j])
            root[i+1][j] = root[i][j] + 1
        if root[i][j+1] == '.': #上
            q.append([i,j+1])
            root[i][j+1] = root[i][j] + 1
        if root[i][j-1] == '.': #下
            q.append([i,j-1])
            root[i][j-1] = root[i][j] + 1
    max = 0
    for i in range(1,h+1):
        for j in range(1,w+1):
            if root[i][j] != '#' and root[i][j] > max:
                max = root[i][j]
    return max

ans = -1
for i in range(1,h+1):
    for j in range(1,w+1):
        k = bfs(i,j)
        if ans < k:
            ans = k
print(ans)

Submission status: Runtime Error

Solution code:
import copy
from collections import deque


def bfs(s, f):
    f[s[0]][s[1]] = 0
    moves = [[1, 0], [-1, 0], [0, 1], [0, -1]]

    q = deque([s])
    while q:
        c = q.popleft()
        for m in moves:
            my, mx = c[0] + m[0], c[1] + m[1]

            if f[my][mx] == ".":
                f[my][mx] = f[c[0]][c[1]] + 1
                q.append([my, mx])
            else:
                continue

    f = sum(f, [])
    return max([x for x in f if type(x) == int])


def main():
    H, W = map(int, input().split())
    field_s = []

    for h in range(H + 2):
        field_s.append(["#"] * (W + 2))
        if 1 <= h <= (H):
            field_s[h][1:-1] = list(map(str, input().rstrip()))

    ans = 0
    for y in range(1, H + 1):
        for x in range(1, W + 1):
            if field_s[y][x] == ".":
                ans = max(ans, bfs([y, x], copy.deepcopy(field_s))

    print(ans)


if __name__ == '__main__':
    main()

Submission status: Runtime Error

Solution code:
import copy
from collections import deque


def bfs(que, field):
    field[que[0]][que[1]] = 0
    moves = [[1, 0], [-1, 0], [0, 1], [0, -1]]

    while que:
        c = que.popleft()
        for m in moves:
            my, mx = c[0] + m[0], c[1] + m[1]

            if field[my][mx] == ".":
                field[my][mx] = field[c[0]][c[1]] + 1
                que.append([my, mx])
            else:
                continue

    field = sum(field, [])
    return max([x for x in field if type(x) == int])


def main():
    H, W = map(int, input().split())
    field_s = []

    for h in range(H + 2):
        field_s.append(["#"] * (W + 2))
        if 1 <= h <= (H):
            field_s[h][1:-1] = list(map(str, input().rstrip()))

    start = []
    for y in range(1, H + 1):
        for x in range(1, W + 1):
            if field_s[y][x] == ".":
                start.append([y, x])

    ans = 0
    for s in start:
        que = deque([s])
        field = copy.deepcopy(field_s)
        ans = max(ans, bfs(que, field))

    print(ans)


if __name__ == '__main__':
    main()

Submission status: Runtime Error

Solution code:
from collections import deque
h,w = map(int,input().split())
s_input = [list(input()) for i in range(h)]

mx = [0,0,1,-1]
my = [1,-1,0,0]

ans = 0
for i in range(h):
    for j in range(w):
        if s_input[i][j]=='#':
            continue
        queue = deque()
        queue.append([j,i])

        visited = [[-1]*w for i in range(h)]
        visited[i][j]=0

        res = 0
        while queue:
            y,x = queue.popleft()
            for k in range(4):
                nx = x+mx[k]
                ny = y+my[k]
                if 0<=nx<w and 0<=ny<h:
                    if visited[ny][nx]!=-1:
                        continue
                    if s_input[ny][nx]=='#':
                        continue
                    visited[ny][nx]=visited[y][x]+1
                    queue.append([nx,ny])
                    res = max(res,visited[ny][nx])
        ans = max(ans,res)
print(ans)

Submission status: Runtime Error

Solution code:
from collections import deque
import numpy as np

H, W = map(int, input().split())
H += 2; W += 2
grid = []
grid.append("#" * W)
for h in range(H-2):
  grid.append("#" + input() + "#")
grid.append("#" * W)

INF = -1
ans = 0
for h in range(1, H-1):
  for w in range(1, W-1):
    
    if grid[h][w]=="#": continue

    dist = np.array([[INF]*W for i in range(H)])
    dist[h][w] = 0 
    q = deque([(h,w)])

    while(q):
      v_h, v_w = q.popleft()
      d_v = dist[v_h][v_w]
      for n_h, n_w in ((v_h, v_w-1),(v_h, v_w+1),(v_h-1, v_w),(v_h+1, v_w)):
        if grid[n_h][n_w]=="#": continue
        d_v = dist[v_h][v_w]
        d_n = d_v + 1
        if (dist[n_h][n_w] == -1) & (d_n > dist[n_h][n_w]):
          continue
        
        dist[n_h][n_w] = d_n
        q.append((n_h,n_w))


    
      dist_m = max(x for x in dist.flatten() if x < INF)
      ans = max(ans, dist_m)

print(ans)

Submission status: Runtime Error

Solution code:
from collections import deque
#import numpy as np

H, W = map(int, input().split())
H += 2; W += 2
grid = []
grid.append("#" * W)
for h in range(H-2):
  grid.append("#" + input() + "#")
grid.append("#" * W)

INF = -1
ans = 0
for h in range(1, H-1):
  for w in range(1, W-1):
    
    if grid[h][w]=="#": continue

    dist = np.array([[INF]*W for i in range(H)])
    dist[h][w] = 0 
    q = deque([(h,w)])

    while(q):
      v_h, v_w = q.popleft()
      d_v = dist[v_h][v_w]
      for n_h, n_w in ((v_h, v_w-1),(v_h, v_w+1),(v_h-1, v_w),(v_h+1, v_w)):
        if grid[n_h][n_w]=="#": continue
        d_v = dist[v_h][v_w]
        d_n = d_v + 1
        if (dist[n_h][n_w] == -1) & (d_n > dist[n_h][n_w]):
          continue
        
        dist[n_h][n_w] = d_n
        q.append((n_h,n_w))


    
      dist_m = max(x for x in dist.flatten() if x < INF)
      ans = max(ans, dist_m)

print(ans)

Submission status: Runtime Error

Solution code:
from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall

H, W = map(int, input().split())
# Inf = 10**9

S = [input() for i in range(H)]
dis = [[0]*(H*W) for i in range(H*W)]

for i in range(H):
    for j in range(W):
        if S[i][j] == "#":
            continue
        if i - 1 >= 0 and S[i-1][j] != "#":
            dis[i*W+j][(i-1)*W+j] = 1
        if i + 1 < H and S[i+1][j] != "#":
            dis[i*W+j][(i+1)*W+j] = 1
        if j - 1 >= 0 and S[i][j-1] != "#":
            dis[i*W+j][i*W+j-1] = 1
        if j + 1 < H and S[i][j+1] != "#":
            dis[i*W+j][i*W+j+1] = 1

g = floyd_warshall(csgraph_from_dense(dis))

max_ans = 0
for i in range(H*W):
    for j in range(H*W):
        if g[i][j] > max_ans and g[i][j] != float("inf"):
            max_ans = g[i][j]

print(int(max_ans))

Submission status: Runtime Error

Solution code:
H, W = map(int, input().split())
Inf = 10**9

S = [input() for i in range(H)]
dis = [[Inf]*(H*W) for i in range(H*W)]

for i in range(H):
    for j in range(W):
        if S[i][j] == "#":
            continue
        if i - 1 >= 0 and S[i-1][j] != "#":
            dis[i*W+j][(i-1)*W+j] = 1
        if i + 1 < H and S[i+1][j] != "#":
            dis[i*W+j][(i+1)*W+j] = 1
        if j - 1 >= 0 and S[i][j-1] != "#":
            dis[i*W+j][i*W+j-1] = 1
        if j + 1 < H and S[i][j+1] != "#":
            dis[i*W+j][i*W+j+1] = 1

for i in range(H*W):
    for j in range(H*W):
        for k in range(H*W):
            dis[j][k] = min(dis[j][i] + dis[i][k], dis[j][k])

max_ans = 0
for i in range(H*W):
    for j in range(H*W):
        if dis[i][j] > max_ans and dis[i][j] != Inf:
            max_ans = dis[i][j]

print(max_ans)

Submission status: Runtime Error

Solution code:
H, W = map(int, input().split())
Inf = 10**9

S = [input() for i in range(H)]
dis = [[Inf]*(H*W) for i in range(H*W)]

for i in range(H):
    for j in range(W):
        if S[i][j] == "#":
            continue
        if i - 1 >= 0 and S[i-1][j] != "#":
            dis[i*W+j][(i-1)*W+j] = 1
        if i + 1 < H and S[i+1][j] != "#":
            dis[i*W+j][(i+1)*W+j] = 1
        if j - 1 >= 0 and S[i][j-1] != "#":
            dis[i*W+j][i*W+j-1] = 1
        if j + 1 < H and S[i][j+1] != "#":
            dis[i*W+j][i*W+j+1] = 1

for i in range(H*W):
    for j in range(H*W):
        for k in range(H*W):
            dis[j][k] = min(dis[j][i] + dis[i][k], dis[j][k])

max_ans = -10**9
for i in range(H*W):
    for j in range(H*W):
        if dis[i][j] > max_ans and dis[i][j] != Inf:
            max_ans = dis[i][j]

print(max_ans)

Submission status: Runtime Error

Solution code:
from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall

H, W = map(int, input().split())
S = [input() for _ in range(H)]

g = [[0] * (H * W) for _ in range(H * W)]
for y in range(H):
    for x in range(W):
        if S[y][x] == '#':
            continue
        if y - 1 >= 0 and S[y - 1][x] != '#':
            g[y * W + x][(y - 1) * W + x] = 1
        if y + 1 < H and S[y + 1][x] != '#':
            g[y * W + x][(y + 1) * W + x] = 1
        if x - 1 >= 0 and S[y][x - 1] != '#':
            g[y * W + x][y * W + x - 1] = 1
        if x + 1 < W and S[y][x + 1] != '#':
            g[y * W + x][y * W + x + 1] = 1
g = floyd_warshall(csgraph_from_dense(g))

result = 0
for i in range(H * W):
    for j in range(H * W):
        if g[i][j] == 0:
            continue
        result = max(result, g[i][j])
print(int(result))

Submission status: Runtime Error

Solution code:
from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall

H, W = map(int, input().split())
S = [input() for _ in range(H)]

g = [[0] * (H * W) for _ in range(H * W)]
for y in range(H):
    for x in range(W):
        if S[y][x] == '#':
            continue
        if y - 1 >= 0 and S[y - 1][x] != '#':
            g[y * W + x][(y - 1) * W + x] = 1
        if y + 1 < H and S[y + 1][x] != '#':
            g[y * W + x][(y + 1) * W + x] = 1
        if x - 1 >= 0 and S[y][x - 1] != '#':
            g[y * W + x][y * W + x - 1] = 1
        if x + 1 < W and S[y][x + 1] != '#':
            g[y * W + x][y * W + x + 1] = 1
g = floyd_warshall(csgraph_from_dense(g))

result = 0
for i in range(H):
    for j in range(W):
        if S[i][j] != '#':
            result = max(result, g[i][j])
print(int(result))

Submission status: Runtime Error

Solution code:
H,W = map(int,input().split())
S = [input() for i in range(H)]

dxy = [(0,1),(1,0),(0,-1),(-1,0)]
from collections import deque
ans = 0
for y in range(H):
    for x in range(W):
        if S[y][x] == '#': continue
        dist = [[0]*W for i in range(H)]
        visited = [[0]*W for i in range(H)]
        visited[y][x] = 1
        q = deque([(x,y)])
        while q:
            x,y = q.popleft()
            for dx,dy in dxy:
                nx,ny = x+dx,y+dy
                if not 0 <= nx < W: continue
                if not 0 <= ny < H: continue
                if visited[ny][nx]: continue
                if S[ny][nx] == '#': continue
                visited[ny][nx] = 1
                dist[ny][nx] = dist[y][x] + 1
                q.append((nx,ny))
        
        for i in range(H):
            ans = max(ans, dist[i])

print(ans)

Submission status: Runtime Error

Solution code:
from collections import deque



H,W = map(int, input().split())
S = [input() for _ in range(H)]

ans = 0
dyx = [(1,0), (0,1),(-1,0), (0,-1)]
for i in range(H):
    for j in range(W):
        if S[i][j] == "#" continue
        dist = [[0 for _ in range(W)] for _ in range(H)] 
        dist[i][j] = 0
        visited = [[False for _ in range(W)] for _ in range(H)]
        visited[i][j] = True
        tmp = 0
        q = deque()
        q.append((i,j))
        while q:
            y,x = q.popleft()
            for dy,dx in dyx:
                ny, nx = y+dy, x+dx
                if not 0 <= ny <= H-1 or not 0 <= nx <= W-1 or visited[ny][nx] == True or S[ny][nx] == "#":
                    continue
                q.append((ny, nx))
                dist[ny][nx] = dist[y][x] + 1
                visited[ny][nx] = True



        for i in range(H):
            ans = max(ans, max(dist[i]))

            

print(ans)

Submission status: Runtime Error

Solution code:
from collections import deque
import math
import copy
H,W = map(int,input().split())
maze = [list(input()) for _ in range(H)]
def bfs(maze,h,w,sx,sy):
    for y in range(h):
        for x in range(w):
            if maze[y][x]=='.':
                maze[y][x]=float('inf')

    maze[sy][sx]=0
    que=deque([[sy,sx]])
    while que:
        y,x=que.popleft()
        for i,j in [(1,0),(0,1),(-1,0),(0,-1)]:
            if 0 <= y+i < H and 0<=x+j<W:
                nexty,nextx=y+i,x+j
                dist=maze[nexty][nextx]
                if dist!='#':
                    if dist>maze[y][x]+1:
                        maze[nexty][nextx]=maze[y][x]+1
                        que.append([nexty,nextx])
    m = 0                   
    for l in maze:
      m = max(m,max([i for i in l if i != '#' and i < 1000000]))
    return m
max_dist = -1  
for si in range(H):
  for sj in range(W):
    if maze[si][sj] == '#':
      continue
    copymaze = copy.deepcopy(maze)
    res = bfs(copymaze,H,W,sj,si)
    max_dist = max(max_dist,res)

print(max_dist)

Submission status: Runtime Error

Solution code:
from collections import deque
import math
import copy
H,W = map(int,input().split())
maze = [list(input()) for _ in range(H)]
tmp = [li for li in  maze]
def bfs(maze,h,w,sx,sy):
    for y in range(h):
        for x in range(w):
            if maze[y][x]=='.':
                maze[y][x]=float('inf')

    maze[sy][sx]=0
    que=deque([[sy,sx]])
    while que:
        y,x=que.popleft()
        for i,j in [(1,0),(0,1),(-1,0),(0,-1)]:
            if 0 <= y+i < H and 0<=x+j<W:
                nexty,nextx=y+i,x+j
                dist=maze[nexty][nextx]
                if dist!='#':
                    if dist>maze[y][x]+1:
                        maze[nexty][nextx]=maze[y][x]+1
                        que.append([nexty,nextx])
    m = 0                   
    for l in maze:
      m = max(m,max([i for i in l if i != '#']))
    return m
max_dist = -1  
for si in range(H):
  for sj in range(W):
    if maze[si][sj] == '#':
      continue
    copymaze = copy.deepcopy(maze)
    res = bfs(copymaze,H,W,sj,si)
    max_dist = max(max_dist,res)

print(max_dist)

Submission status: Runtime Error

Solution code:
import sys
sys.setrecursionlimit(10000)

import numpy as np

h,w = map(int,input().split())
s = []

for i in range(h):
    s.append(list(input()))

from collections import deque

def bfs(i,j,dist):
    seen[i][j] = dist
    lis = [[i-1,j],[i,j-1],[i+1,j],[i,j+1]]
    for place in lis:
        if place[0]<0 or place[0]>=h or place[1]<0 or place[1]>=w:
            continue
        if seen[place[0]][place[1]] != -1 or s[place[0]][place[1]]=="#":
            continue
        que.append([place[0],place[1],dist+1])
    if len(que):
        new = que.popleft()
        bfs(new[0],new[1],new[2])
    else:
        return


mx = 0
for i in range(h):
    for  j in range(w):
        if s[i][j]=="#":
            continue
        seen = [[-1 for _ in range(w)]for _ in range(h)]
        que = deque()
        bfs(i,j,0)
        ast = np.array(seen)
        tmp = np.amax(ast)
        mx = max(mx,tmp)
        #print(seen)
            #print(*seen,sep="\n")
print(mx)

Submission status: Runtime Error

Solution code:
import sys
sys.setrecursionlimit(2000)
h,w = map(int,input().split())
s = []

for i in range(h):
    s.append(list(input()))

from collections import deque

def bfs(i,j,dist):
    seen[i][j] = dist
    lis = [[i-1,j],[i,j-1],[i+1,j],[i,j+1]]
    for place in lis:
        if place[0]<0 or place[0]>=h or place[1]<0 or place[1]>=w:
            continue
        if seen[place[0]][place[1]] != -1 or s[place[0]][place[1]]=="#":
            continue
        que.append([place[0],place[1],dist+1])
    if len(que):
        new = que.popleft()
        bfs(new[0],new[1],new[2])
    else:
        return


mx = 0
for i in range(h):
    for  j in range(w):
        if s[i][j]=="#":
            continue
        seen = [[-1 for _ in range(w)]for _ in range(h)]
        que = deque()
        bfs(i,j,0)
        mx = max(mx,max(max(seen)))
        #print(seen)
#print(seen)
print(mx)