Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
# 縦(H)x横(W)
H, W = map(int, input().split())
# 魔法使いの座標
CH, CW = map(int, input().split())
# ゴール
DH, DW = map(int, input().split())
# マップ
S = [list(input()) for _ in range(H)]
# 移動Aの動き方
move_a = [(0, 1), (0, -1), (1, 0), (-1, 0)]
# 移動Bの動き方
move_b = [(x, y) for x in range(-2, 3)
          for y in range(-2, 3) if (x, y) not in move_a + [(0, 0)]]

INF = 10 ** 10
# 各マスへの移動コスト
path = [[INF] * W for _ in range(H)]

q = deque()
path[CH-1][CW-1] = 0
q.append((CH-1, CW-1, 0))

while q:

    x, y, s = q.popleft()

    # 移動Aについて
    for dx, dy in move_a:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s:
            path[nx][ny] = s
            q.appendleft((nx, ny, s))

# 移動Bについて
    for dx, dy in move_b:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s+1:
            path[nx][ny] = s+1
            q.append((nx, ny, s+1))


print(path[DH-1][DW-1]) if path[DH-1][DW-1] < INF else print(-1)

Fixed submission:
from collections import deque
# 縦(H)x横(W)
H, W = map(int, input().split())
# 魔法使いの座標
CH, CW = map(int, input().split())
# ゴール
DH, DW = map(int, input().split())
# マップ
S = [list(input()) for _ in range(H)]
# 移動Aの動き方
move_a = [(0, 1), (0, -1), (1, 0), (-1, 0)]
# 移動Bの動き方
move_b = [(x, y) for x in range(-2, 3)
          for y in range(-2, 3) if (x, y) not in move_a + [(0, 0)]]

INF = 10 ** 10
# 各マスへの移動コスト
path = [[INF] * W for _ in range(H)]

q = deque()
path[CH-1][CW-1] = 0
q.append((CH-1, CW-1, 0))

while q:

    x, y, s = q.popleft()

    # 移動Aについて
    for dx, dy in move_a:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s:
            path[nx][ny] = s
            q.appendleft((nx, ny, s))

# 移動Bについて
    for dx, dy in move_b:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s+1:
            path[nx][ny] = s+1
            q.append((nx, ny, s+1))


print(path[DH-1][DW-1]) if path[DH-1][DW-1] < INF else print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
# 縦(H)x横(W)
H, W = map(int, input().split())
# 魔法使いの座標
CH, CW = map(int, input().split())
# ゴール
DH, DW = map(int, input().split())
# マップ
S = [list(input()) for _ in range(H)]
# 移動Aの動き方
move_a = [(0, 1), (0, -1), (1, 0), (-1, 0)]
# 移動Bの動き方
move_b = [(x, y) for x in range(-2, 3)
          for y in range(-2, 3) if (x, y) not in move_a + [(0, 0)]]

INF = 10 ** 10

# 各マスへの移動コスト
path = [[INF] * W for _ in range(H)]

q = deque()
path[CH-1][CW-1] = 0
q.append((CH-1, CW-1, 0))

while q:

    x, y, s = q.popleft()

    # 移動Aについて
    for dx, dy in move_a:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s:
            path[nx][ny] = s
            q.appendleft((nx, ny, s))

    # 移動Bについて
        for dx, dy in move_b:
            nx = x + dx
            ny = y + dy

            if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s+1:
                path[nx][ny] = s+1
                q.append((nx, ny, s+1))


print(path[DH-1][DW-1]) if path[DH-1][DW-1] < INF else print(-1)


Fixed submission:
from collections import deque
# 縦(H)x横(W)
H, W = map(int, input().split())
# 魔法使いの座標
CH, CW = map(int, input().split())
# ゴール
DH, DW = map(int, input().split())
# マップ
S = [list(input()) for _ in range(H)]
# 移動Aの動き方
move_a = [(0, 1), (0, -1), (1, 0), (-1, 0)]
# 移動Bの動き方
move_b = [(x, y) for x in range(-2, 3)
          for y in range(-2, 3) if (x, y) not in move_a + [(0, 0)]]

INF = 10 ** 10
# 各マスへの移動コスト
path = [[INF] * W for _ in range(H)]

q = deque()
path[CH-1][CW-1] = 0
q.append((CH-1, CW-1, 0))

while q:

    x, y, s = q.popleft()

    # 移動Aについて
    for dx, dy in move_a:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s:
            path[nx][ny] = s
            q.appendleft((nx, ny, s))

# 移動Bについて
    for dx, dy in move_b:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s+1:
            path[nx][ny] = s+1
            q.append((nx, ny, s+1))


print(path[DH-1][DW-1]) if path[DH-1][DW-1] < INF else print(-1)

Buggy python submission (verdict: Time Limit Exceeded):

from collections import deque
# 縦(H)x横(W)
H, W = map(int, input().split())
# 魔法使いの座標
CH, CW = map(int, input().split())
# ゴール
DH, DW = map(int, input().split())
# マップ
S = [list(input()) for _ in range(H)]
# 移動Aの動き方
move_a = [(0, 1), (0, -1), (1, 0), (-1, 0)]
# 移動Bの動き方
move_b = [(x, y) for x in range(-2, 3)
          for y in range(-2, 3) if (x, y) not in move_a + [(0, 0)]]

# 各マスへの移動コスト
path = [[10**10] * W for _ in range(H)]

q = deque()
path[CH-1][CW-1] = 0
q.append((CH-1, CW-1, 0))

while q:

    x, y, s = q.popleft()

    # 移動Aについて
    for dx, dy in move_a:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s:
            path[nx][ny] = s
            q.appendleft((nx, ny, s))

    # 移動Bについて
        for dx, dy in move_b:
            nx = x + dx
            ny = y + dy

            if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s+1:
                path[nx][ny] = s+1
                q.append((nx, ny, s+1))


print(path[DH-1][DW-1]) if path[DH-1][DW-1] < 10 ** 10 else print(-1)


Fixed submission:
from collections import deque
# 縦(H)x横(W)
H, W = map(int, input().split())
# 魔法使いの座標
CH, CW = map(int, input().split())
# ゴール
DH, DW = map(int, input().split())
# マップ
S = [list(input()) for _ in range(H)]
# 移動Aの動き方
move_a = [(0, 1), (0, -1), (1, 0), (-1, 0)]
# 移動Bの動き方
move_b = [(x, y) for x in range(-2, 3)
          for y in range(-2, 3) if (x, y) not in move_a + [(0, 0)]]

INF = 10 ** 10
# 各マスへの移動コスト
path = [[INF] * W for _ in range(H)]

q = deque()
path[CH-1][CW-1] = 0
q.append((CH-1, CW-1, 0))

while q:

    x, y, s = q.popleft()

    # 移動Aについて
    for dx, dy in move_a:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s:
            path[nx][ny] = s
            q.appendleft((nx, ny, s))

# 移動Bについて
    for dx, dy in move_b:
        nx = x + dx
        ny = y + dy

        if 0 <= nx < H and 0 <= ny < W and S[nx][ny] == "." and path[nx][ny] > s+1:
            path[nx][ny] = s+1
            q.append((nx, ny, s+1))


print(path[DH-1][DW-1]) if path[DH-1][DW-1] < INF else print(-1)