Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.append((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()


Fixed submission:
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.appendleft((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict, deque

H, W = map(int, input().split())
ch, cw = map(int, input().split())
dh, dw = map(int, input().split())
ch -= 1
cw -= 1
dh -= 1
dw -= 1

maze = []
for _ in range(H):
    row = list(input())
    maze.append(row)

def dfs(i, j, cnt):
    mapped[i][j] = cnt

    for dx, dy in [[-1, 0], [1, 0], [0, -1], [0, 1]]:
        x = i + dx
        y = j + dy
        if 0 <= x < H and 0 <= y < W and maze[x][y] == "." and mapped[x][y] == -1:
            dfs(x, y, cnt)
        elif 0 <= x < H and 0 <= y < W and maze[x][y] == "#" and (i, j) not in edges[cnt]:
            edges[cnt].add((i, j))
            

cnt = 0
mapped = [[-1] * W for _ in range(H)]
edges = defaultdict(set)
for i in range(H):
    for j in range(W):
        if maze[i][j] == "." and mapped[i][j] == -1:
            dfs(i, j, cnt)
            cnt += 1

invalid_pos = set([(-1, 0), (1, 0), (0, -1), (0, 1), (0, 0)])
# edges からワープで移動できる島を繋いで、グラフを作る
g = defaultdict(set)
for num in edges:
    for i, j in edges[num]:
        for dx in range(-2, 3):
            for dy in range(-2, 3):
                if (dx, dy) in  invalid_pos: continue
                x = i + dx
                y = j + dy
                if 0 <= x < H and 0 <= y < W and mapped[x][y] != -1 and mapped[x][y] != num and mapped[x][y] not in g[num]:
                    g[num].add(mapped[x][y])
                    g[mapped[x][y]].add(num)

# gでのstart, endの最短距離をbfsで求める
start = mapped[ch][cw]
end = mapped[dh][dw]
q = deque([(start, 0),])
seen = set()

isFind = False
while q:
    size = len(q)
    for _ in range(size):
        node, d = q.popleft()
        seen.add(node)
        if node == end:
            print(d)
            isFind = True
            break
        for adj in g[node]:
            if adj not in seen:
                q.append((adj, d+1))
    if isFind:
        break

if not isFind:
    print(-1)



Fixed submission:
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.appendleft((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict, deque

H, W = map(int, input().split())
ch, cw = map(int, input().split())
dh, dw = map(int, input().split())
ch -= 1
cw -= 1
dh -= 1
dw -= 1

maze = []
for _ in range(H):
    row = list(input())
    maze.append(row)

def dfs(i, j, cnt):
    mapped[i][j] = cnt

    for dx, dy in [[-1, 0], [1, 0], [0, -1], [0, 1]]:
        x = i + dx
        y = j + dy
        if 0 <= x < H and 0 <= y < W and maze[x][y] == "." and mapped[x][y] == -1:
            dfs(x, y, cnt)
        elif 0 <= x < H and 0 <= y < W and maze[x][y] == "#" and (i, j) not in edges[cnt]:
            edges[cnt].add((i, j))

cnt = 0
mapped = [[-1] * W for _ in range(H)]
edges = defaultdict(set)
for i in range(H):
    for j in range(W):
        if maze[i][j] == "." and mapped[i][j] == -1:
            dfs(i, j, cnt)
            cnt += 1

invalid_pos = set([(-1, 0), (1, 0), (0, -1), (0, 1), (0, 0)])
# edges からワープで移動できる島を繋いで、グラフを作る
g = defaultdict(set)
for num in edges:
    for i, j in edges[num]:
        for dx in range(-2, 3):
            for dy in range(-2, 3):
                if (dx, dy) in  invalid_pos: continue
                x = i + dx
                y = j + dy
                if 0 <= x < H and 0 <= y < W and mapped[x][y] != -1 and mapped[x][y] != num and mapped[x][y] not in g[num]:
                    g[num].add(mapped[x][y])
                    g[mapped[x][y]].add(num)

# gでのstart, endの最短距離をbfsで求める
start = mapped[ch][cw]
end = mapped[dh][dw]
q = deque([(start, 0),])
seen = set()

isFind = False
while q:
    size = len(q)
    for _ in range(size):
        node, d = q.popleft()
        seen.add(node)
        if node == end:
            print(d)
            isFind = True
            break
        for adj in g[node]:
            if adj not in seen:
                q.append((adj, d+1))
    if isFind:
        break

if not isFind:
    print(-1)



Fixed submission:
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.appendleft((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict, deque

H, W = map(int, input().split())
ch, cw = map(int, input().split())
dh, dw = map(int, input().split())
ch -= 1
cw -= 1
dh -= 1
dw -= 1

maze = []
for _ in range(H):
    row = list(input())
    maze.append(row)

def dfs(i, j, cnt):
    mapped[i][j] = cnt

    for dx, dy in [[-1, 0], [1, 0], [0, -1], [0, 1]]:
        x = i + dx
        y = j + dy
        if 0 <= x < H and 0 <= y < W and maze[x][y] == "." and mapped[x][y] == -1:
            dfs(x, y, cnt)
        elif 0 <= x < H and 0 <= y < W and maze[x][y] == "#":
            edges[cnt].add((i, j))

cnt = 0
mapped = [[-1] * W for _ in range(H)]
edges = defaultdict(set)
for i in range(H):
    for j in range(W):
        if maze[i][j] == "." and mapped[i][j] == -1:
            dfs(i, j, cnt)
            cnt += 1

invalid_pos = set([(-1, 0), (1, 0), (0, -1), (0, 1)])
# edges からワープで移動できる島を繋いで、グラフを作る
g = defaultdict(set)
for num in edges:
    for i, j in edges[num]:
        for dx in range(-2, 3):
            for dy in range(-2, 3):
                if (dx, dy) in  invalid_pos: continue
                x = i + dx
                y = j + dy
                if 0 <= x < H and 0 <= y < W and mapped[x][y] != -1 and mapped[x][y] != num and mapped[x][y] not in g[num]:
                    g[num].add(mapped[x][y])
                    g[mapped[x][y]].add(num)

# gでのstart, endの最短距離をbfsで求める
start = mapped[ch][cw]
end = mapped[dh][dw]
q = deque([(start, 0),])
seen = set()

isFind = False
while q:
    size = len(q)
    for _ in range(size):
        node, d = q.popleft()
        seen.add(node)
        if node == end:
            print(d)
            isFind = True
            break
        for adj in g[node]:
            if adj not in seen:
                q.append((adj, d+1))
    if isFind:
        break

if not isFind:
    print(-1)



Fixed submission:
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.appendleft((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict, deque

H, W = map(int, input().split())
ch, cw = map(int, input().split())
dh, dw = map(int, input().split())
ch -= 1
cw -= 1
dh -= 1
dw -= 1

maze = []
for _ in range(H):
    row = list(input())
    maze.append(row)

def dfs(i, j, cnt):
    mapped[i][j] = cnt

    for dx, dy in [[-1, 0], [1, 0], [0, -1], [0, 1]]:
        x = i + dx
        y = j + dy
        if 0 <= x < H and 0 <= y < W and maze[x][y] == "." and mapped[x][y] == -1:
            dfs(x, y, cnt)
        elif 0 <= x < H and 0 <= y < W and maze[x][y] == "#":
            edges[cnt].add((i, j))

cnt = 0
mapped = [[-1] * W for _ in range(H)]
edges = defaultdict(set)
for i in range(H):
    for j in range(W):
        if maze[i][j] == "." and mapped[i][j] == -1:
            dfs(i, j, cnt)
            cnt += 1

invalid_pos = set([(-1, 0), (1, 0), (0, -1), (0, 1)])
# edges からワープで移動できる島を繋いで、グラフを作る
g = defaultdict(set)
for num in edges:
    for i, j in edges[num]:
        for dx in range(-2, 3):
            for dy in range(-2, 3):
                if (dx, dy) in  invalid_pos: continue
                x = i + dx
                y = j + dy
                if 0 <= x < H and 0 <= y < W and mapped[x][y] != -1 and mapped[x][y] != num and mapped[x][y] not in g[num]:
                    g[num].add(mapped[x][y])
                    g[mapped[x][y]].add(num)

# gでのstart, endの最短距離をbfsで求める
start = mapped[ch][cw]
end = mapped[dh][dw]
q = deque([(start, 0),])
seen = set()

isFind = False
while q:
    size = len(q)
    for _ in range(size):
        node, d = q.popleft()
        seen.add(node)
        if node == end:
            print(d)
            isFind = True
            break
        for adj in g[node]:
            if adj not in seen:
                q.append((adj, d+1))
    if isFind:
        break

if not isFind:
    print(-1)



Fixed submission:
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.appendleft((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict, deque

H, W = map(int, input().split())
ch, cw = map(int, input().split())
dh, dw = map(int, input().split())
ch -= 1
cw -= 1
dh -= 1
dw -= 1

maze = []
for _ in range(H):
    row = list(input())
    maze.append(row)

def dfs(i, j, cnt):
    mapped[i][j] = cnt

    for dx, dy in [[-1, 0], [1, 0], [0, -1], [0, 1]]:
        x = i + dx
        y = j + dy
        if 0 <= x < H and 0 <= y < W and maze[x][y] == "." and mapped[x][y] == -1:
            dfs(x, y, cnt)
        elif 0 <= x < H and 0 <= y < W and maze[x][y] == "#":
            edges[cnt].add((i, j))

cnt = 0
mapped = [[-1] * W for _ in range(H)]
edges = defaultdict(set)
for i in range(H):
    for j in range(W):
        if maze[i][j] == "." and mapped[i][j] == -1:
            dfs(i, j, cnt)
            cnt += 1

# edges からワープで移動できる島を繋いで、グラフを作る
g = defaultdict(set)
for num in edges:
    for i, j in edges[num]:
        for dx in range(-2, 3):
            for dy in range(-2, 3):
                x = i + dx
                y = j + dy
                if 0 <= x < H and 0 <= y < W and mapped[x][y] != -1 and mapped[x][y] != num:
                    g[num].add(mapped[x][y])
                    g[mapped[x][y]].add(num)

# gでのstart, endの最短距離をbfsで求める
start = mapped[ch][cw]
end = mapped[dh][dw]
q = deque([(start, 0),])
seen = set()

isFind = False
while q:
    size = len(q)
    for _ in range(size):
        node, d = q.popleft()
        seen.add(node)
        if node == end:
            print(d)
            isFind = True
            break
        for adj in g[node]:
            if adj not in seen:
                q.append((adj, d+1))
    if isFind:
        break

if not isFind:
    print(-1)



Fixed submission:
from collections import defaultdict, deque

def main():
    H, W = map(int, input().split())
    ch, cw = map(int, input().split())
    dh, dw = map(int, input().split())
    ch -= 1
    cw -= 1
    dh -= 1
    dw -= 1
    maze = [input() for _ in range(H)]

    INF = 10**12
    path = [[INF] * W for _ in range(H)] # 各マスへの移動コスト
    
    # walk:移動A, warp:移動B
    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]

    q = deque()
    path[ch][cw] = 0
    q.append((ch, cw, 0))

    while q:
        x, y, s = q.popleft()
        for dx, dy in walk: #移動A
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s:
                path[nx][ny] = s
                q.appendleft((nx, ny, s)) # なぜleft?

        for dx, dy in warp: #移動B
            nx = x + dx
            ny = y + dy
            if 0 <= nx < H and 0 <= ny < W and maze[nx][ny] == "." and path[nx][ny] > s + 1:
                path[nx][ny] = s + 1
                q.append((nx, ny, s+1)) # なぜright?

    ans = path[dh][dw] if path[dh][dw] != INF else "-1"
    print(ans)

if __name__ == "__main__":
    main()