Buggy python submission (verdict: Runtime Error):
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
            fast += 1
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Fixed submission:
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    fast = 0
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
            fast += 1
    if fast < 3:
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Fixed submission:
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    fast = 0
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
            fast += 1
    if fast < 4:
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Fixed submission:
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
    for i in range(-2,3):
        for j in range(-2,3):
            nx = x+i; ny = y+j
            if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                nq.append([nx,ny,z+1])
                mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)

Fixed submission:
h,w = list(map(int,input().split()))
sx, sy = list(map(int,input().split()))
gx, gy = list(map(int,input().split()))
maze = [list(input()) for _ in range(h)]
sx -= 1; sy -= 1; gx -= 1; gy -= 1

mx = [0,1,0,-1]
my = [1,0,-1,0]
mazemap = [[10**9]*w for _ in range(h)]
from collections import deque
q = deque()
nq = deque()
q.append([sx,sy,0])

while q or nq:
    x,y,z = q.popleft() if q else nq.popleft()
    if x == gx and y == gy:
        ans = z
        break
    for i in range(4):
        nx = x + mx[i]; ny = y + my[i]
        if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z:
            q.append([nx,ny,z])
            mazemap[nx][ny] = z
        for i in range(-2,3):
            for j in range(-2,3):
                nx = x+i; ny = y+j
                if 0 <= nx < h and 0 <= ny < w and maze[nx][ny] != "#" and mazemap[nx][ny] > z+1:
                    nq.append([nx,ny,z+1])
                    mazemap[nx][ny] = z+1
else:
    ans = -1

print(ans)