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

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

dist = [[-1]*w for _ in range(h)]
dist[sh][sw] = 0
q = deque([(0,sh,sw)])
warpq = deque([])

while q or warpq:
    while q:

        d,vsh,vsw = q.popleft()

        flag = 0
        
        for dh,dw in [(-1,0),(1,0),(0,-1),(0,1)]:
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if s[newh][neww] == "#":
                if flag ==0:
                    warpq.append((d,vsh,vsw))
                    flag = 1
                continue

            if dist[newh][neww] == -1:
                dist[newh][neww] = d
                q.append((d,newh,neww))

    while warpq:

        d,vsh,vsw = warpq.popleft()
        for dh in range(-2,3):
            for dw in range(-2,3):
                newh = vsh+dh
                neww = vsw+dw
                if newh<0 or h<=newh or neww<0 or w<=neww: continue
                if abs(dh)+abs(dw)<=0: continue
                if s[newh][neww] == "#": continue

                if dist[newh][neww] == -1:
                    dist[newh][neww] = d+1
                    q.append((d+1,newh,neww))
            
print(dist[gh][gw])

Fixed submission:
from collections import deque

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

dist = [[-1]*w for _ in range(h)]
dist[sh][sw] = 0
q = deque([(0,sh,sw)])
warpq = deque([])

while q or warpq:
    while q:

        d,vsh,vsw = q.popleft()

        flag = 0
        
        for dh,dw in [(-1,0),(1,0),(0,-1),(0,1)]:
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if s[newh][neww] == "#":
                if flag ==0:
                    warpq.append((d,vsh,vsw))
                    flag = 1
                continue

            if dist[newh][neww] == -1:
                dist[newh][neww] = d
                q.append((d,newh,neww))

    while warpq:

        d,vsh,vsw = warpq.popleft()
        for dh in range(-2,3):
            for dw in range(-2,3):
                newh = vsh+dh
                neww = vsw+dw
                if newh<0 or h<=newh or neww<0 or w<=neww: continue
                if abs(dh)+abs(dw)<=0: continue
                if s[newh][neww] == "#": continue

                if dist[newh][neww] == -1:
                    dist[newh][neww] = d+1
                    q.append((d+1,newh,neww))
            
print(dist[gh][gw])

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

INF = 10**7
dist = [[INF]*w for _ in range(h)]
dist[sh][sw] = 0
q = [(0,sh,sw)]
flag = 0
while q:
    
    d,vsh,vsw = heapq.heappop(q)
    
    for dh in range(-2,3):
        for dw in range(-2,3):
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if dh == 0 and dw==0: continue
            if s[newh][neww] == "#": continue
                
            if abs(dh)+abs(dw)==1:
                if dist[newh][neww] > d:
                    dist[newh][neww] = d
                    if newh == gh and neww == gw: flag
                    heapq.heappush(q,(d,newh,neww))
            else:
                if dist[newh][neww] > d+1:
                    dist[newh][neww] = d+1
                    heapq.heappush(q,(d+1,newh,neww))
    if flag: break
if dist[gh][gw] == INF: print(-1)
else: print(dist[gh][gw])

Fixed submission:
from collections import deque

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

dist = [[-1]*w for _ in range(h)]
dist[sh][sw] = 0
q = deque([(0,sh,sw)])
warpq = deque([])

while q or warpq:
    while q:

        d,vsh,vsw = q.popleft()

        flag = 0
        
        for dh,dw in [(-1,0),(1,0),(0,-1),(0,1)]:
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if s[newh][neww] == "#":
                if flag ==0:
                    warpq.append((d,vsh,vsw))
                    flag = 1
                continue

            if dist[newh][neww] == -1:
                dist[newh][neww] = d
                q.append((d,newh,neww))

    while warpq:

        d,vsh,vsw = warpq.popleft()
        for dh in range(-2,3):
            for dw in range(-2,3):
                newh = vsh+dh
                neww = vsw+dw
                if newh<0 or h<=newh or neww<0 or w<=neww: continue
                if abs(dh)+abs(dw)<=0: continue
                if s[newh][neww] == "#": continue

                if dist[newh][neww] == -1:
                    dist[newh][neww] = d+1
                    q.append((d+1,newh,neww))
            
print(dist[gh][gw])

Buggy python submission (verdict: Runtime Error):
import heapq

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

INF = 10**7
dist = [[INF]*w for _ in range(h)]
dist[sh][sw] = 0
q = [(0,sh,sw)]

while q:
    
    d,vsh,vsw = heapq.heappop(q)
    
    for dh in range(-2,3):
        for dw in range(-2,3):
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if dh == 0 and dw==0: continue
            if s[newh][neww] == "#": continue
                
            if abs(dh)+abs(dw)==1:
                if dist[newh][neww] > d:
                    dist[newh][neww] = d
                    if newh == gh and neww = gw: break
                    heapq.heappush(q,(d,newh,neww))
            else:
                if dist[newh][neww] > d+1:
                    dist[newh][neww] = d+1
                    heapq.heappush(q,(d+1,newh,neww))
                    
if dist[gh][gw] == INF: print(-1)
else: print(dist[gh][gw])

Fixed submission:
from collections import deque

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

dist = [[-1]*w for _ in range(h)]
dist[sh][sw] = 0
q = deque([(0,sh,sw)])
warpq = deque([])

while q or warpq:
    while q:

        d,vsh,vsw = q.popleft()

        flag = 0
        
        for dh,dw in [(-1,0),(1,0),(0,-1),(0,1)]:
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if s[newh][neww] == "#":
                if flag ==0:
                    warpq.append((d,vsh,vsw))
                    flag = 1
                continue

            if dist[newh][neww] == -1:
                dist[newh][neww] = d
                q.append((d,newh,neww))

    while warpq:

        d,vsh,vsw = warpq.popleft()
        for dh in range(-2,3):
            for dw in range(-2,3):
                newh = vsh+dh
                neww = vsw+dw
                if newh<0 or h<=newh or neww<0 or w<=neww: continue
                if abs(dh)+abs(dw)<=0: continue
                if s[newh][neww] == "#": continue

                if dist[newh][neww] == -1:
                    dist[newh][neww] = d+1
                    q.append((d+1,newh,neww))
            
print(dist[gh][gw])

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

INF = 10**7
dist = [[INF]*w for _ in range(h)]
dist[sh][sw] = 0
q = [(0,sh,sw)]

while q:
    
    d,vsh,vsw = heapq.heappop(q)
    
    for dh in range(-2,3):
        for dw in range(-2,3):
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if dh == 0 and dw==0: continue
            if s[newh][neww] == "#": continue
                
            if abs(dh)+abs(dw)==1:
                if dist[newh][neww] > d:
                    dist[newh][neww] = d
                    heapq.heappush(q,(d,newh,neww))
            else:
                if dist[newh][neww] > d+1:
                    dist[newh][neww] = d+1
                    heapq.heappush(q,(d+1,newh,neww))
                    
if dist[gh][gw] == INF: print(-1)
else: print(dist[gh][gw])

Fixed submission:
from collections import deque

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

dist = [[-1]*w for _ in range(h)]
dist[sh][sw] = 0
q = deque([(0,sh,sw)])
warpq = deque([])

while q or warpq:
    while q:

        d,vsh,vsw = q.popleft()

        flag = 0
        
        for dh,dw in [(-1,0),(1,0),(0,-1),(0,1)]:
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if s[newh][neww] == "#":
                if flag ==0:
                    warpq.append((d,vsh,vsw))
                    flag = 1
                continue

            if dist[newh][neww] == -1:
                dist[newh][neww] = d
                q.append((d,newh,neww))

    while warpq:

        d,vsh,vsw = warpq.popleft()
        for dh in range(-2,3):
            for dw in range(-2,3):
                newh = vsh+dh
                neww = vsw+dw
                if newh<0 or h<=newh or neww<0 or w<=neww: continue
                if abs(dh)+abs(dw)<=0: continue
                if s[newh][neww] == "#": continue

                if dist[newh][neww] == -1:
                    dist[newh][neww] = d+1
                    q.append((d+1,newh,neww))
            
print(dist[gh][gw])

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

INF = 10**7
dist = [[INF]*w for _ in range(h)]
dist[sh][sw] = 0
q = [(0,sh,sw)]

while q:
    
    d,vsh,vsw = heapq.heappop(q)
    
    for dh in range(-2,3):
        for dw in range(-2,3):
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if dh == 0 and dw==0: continue
            if s[newh][neww] == "#": continue
                
            if abs(dh)+abs(dw)==1:
                if dist[newh][neww] > d:
                    dist[newh][neww] = d
                    heapq.heappush(q,(d,newh,neww))
            else:
                if dist[newh][neww] > d+1:
                    dist[newh][neww] = d+1
                    heapq.heappush(q,(d+1,newh,neww))
                    
if dist[gh][gw] == INF: print(-1)
else: print(dist[gh][gw])

Fixed submission:
from collections import deque

h,w = map(int,input().split())
sh,sw = map(int,input().split())
gh,gw = map(int,input().split())
s = [input() for _ in range(h)]

sh-=1; sw-=1; gh-=1; gw-=1;

dist = [[-1]*w for _ in range(h)]
dist[sh][sw] = 0
q = deque([(0,sh,sw)])
warpq = deque([])

while q or warpq:
    while q:

        d,vsh,vsw = q.popleft()

        flag = 0
        
        for dh,dw in [(-1,0),(1,0),(0,-1),(0,1)]:
            newh = vsh+dh
            neww = vsw+dw
            if newh<0 or h<=newh or neww<0 or w<=neww: continue
            if s[newh][neww] == "#":
                if flag ==0:
                    warpq.append((d,vsh,vsw))
                    flag = 1
                continue

            if dist[newh][neww] == -1:
                dist[newh][neww] = d
                q.append((d,newh,neww))

    while warpq:

        d,vsh,vsw = warpq.popleft()
        for dh in range(-2,3):
            for dw in range(-2,3):
                newh = vsh+dh
                neww = vsw+dw
                if newh<0 or h<=newh or neww<0 or w<=neww: continue
                if abs(dh)+abs(dw)<=0: continue
                if s[newh][neww] == "#": continue

                if dist[newh][neww] == -1:
                    dist[newh][neww] = d+1
                    q.append((d+1,newh,neww))
            
print(dist[gh][gw])