Problem p02579 (python)

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 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])

Buggy 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])