Buggy python submission (verdict: Runtime Error):
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

#score = np.zeros((H, W), dtype=int)
#score[:, :] = INF
score = [[INF] * W for _ in range(W)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Buggy python submission (verdict: Runtime Error):
import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = np.zeros((H, W), dtype=int)
score[:, :] = INF
score[Ch, Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h, w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y, x] > s:
            score[y, x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h, w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y, x] > s + 1:
            score[y, x] = s + 1
            candidates.append((y, x))

if score[Dh, Dw] == INF:
    print(-1)
else:
    print (score[Dh, Dw])


Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Buggy python submission (verdict: Time Limit Exceeded):
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())
maze = [input() for _ in range(H)]

INF = 10 ** 12
path = [[INF] * W for _ in range(H)]  # path: 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))  # 移動Aの場合はコスト0. キューの先頭に追加する.
    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))  # 移動Bの場合はコスト1. キューの最後尾に追加する.
    
ans = path[Dh][Dw] if path[Dh][Dw] < INF else '-1'
print(ans)

Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = np.zeros((H, W), dtype=int)
score[:, :] = INF
score[Ch, Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h, w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y, x] > s:
            score[y, x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h, w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y, x] > s + 1:
            score[y, x] = s + 1
            candidates.append((y, x))

if score[Dh, Dw] == INF:
    print(-1)
else:
    print (score[Dh, Dw])

Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = np.zeros((H, W), dtype=int)
score[:, :] = INF
score[Ch, Cw] = 0

#visited = np.zeros((H, W), dtype=bool)

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y, x] > score[h, w]:
            score[y, x] = score[h, w]
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y, x] > score[h, w] + 1:
            score[y, x] = score[h, w] + 1
            candidates.append((y, x))

if score[Dh, Dw] == INF:
    print(-1)
else:
    print (score[Dh, Dw])




Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np
from collections import 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 i in range(H):
    maze.append(input())

INF = 10 ** 12

score = np.zeros((H, W), dtype=int)
score[:, :] = INF
score[Ch, Cw] = 0

#visited = np.zeros((H, W), dtype=bool)

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y, x] > score[h, w]:
            score[y, x] = score[h, w]
            candidates.appendleft((y, x))
    # warp
    #if not moved: 
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y, x] > score[h, w] + 1:
            score[y, x] = score[h, w] + 1
            candidates.append((y, x))

if score[Dh, Dw] == INF:
    print(-1)
else:
    print (score[Dh, Dw])

Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np
from queue import Queue

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 i in range(H):
    maze.append(input())

INF = 10 ** 12

score = np.zeros((H, W), dtype=int)
score[:, :] = INF

score[Ch, Cw] = 0

#visited = np.zeros((H, W), dtype=bool)

candidates = Queue()
candidates.put((Ch, Cw))

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 not candidates.empty():
    h, w = candidates.get()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y, x] > score[h, w]:
            score[y, x] = score[h, w]
            candidates.put((y, x))
    # warp
    #if not moved: 
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y, x] > score[h, w] + 1:
            score[y, x] = score[h, w] + 1
            candidates.put((y, x))

if score[Dh, Dw] == INF:
    print(-1)
else:
    print (score[Dh, Dw])

Fixed submission:
#import numpy as np
from collections import 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 = [input() for _ in range(H)]

INF = 10 ** 12

score = [[INF] * W for _ in range(H)]

score[Ch][Cw] = 0

candidates = deque()
candidates.append((Ch, Cw))

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 candidates:
    h, w = candidates.popleft()
    # move
    for dh, dw in walk:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue        
        if maze[y][x] == '.' and score[y][x] > s:
            score[y][x] = s
            candidates.appendleft((y, x))
    # warp
    for dh, dw in warp:
        y = h + dh
        x = w + dw
        s = score[h][w]
        if y < 0 or H <= y:
            continue
        if x < 0 or W <= x:
            continue
        if maze[y][x] == '.' and score[y][x] > s + 1:
            score[y][x] = s + 1
            candidates.append((y, x))

if score[Dh][Dw] == INF:
    print(-1)
else:
    print (score[Dh][Dw])