Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())
s=[list(input()) for i in range(h)]

#幅優先で解く。
dx=[1,0,-1,0]
dy=[0,1,0,-1]
def bfs():
  maze=[[-1]*w for i in range(h)]
  maze[ch-1][cw-1]=0
  qu=deque([])
  qu.append((cw-1,ch-1))
  magic=0
  
  while qu:
    x,y=qu.popleft()
    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        nx=i
        ny=j
        if 0<=nx<=w-1 and 0<=ny<=h-1 and s[ny][nx]=="." and (maze[ny][nx]==-1 or maze[ny][nx]>maze[y][x]+1):
          qu.append((nx,ny))
          maze[ny][nx]=maze[y][x]+1
    for i in range(4):
      nx=dx[i]+x
      ny=dy[i]+y
      
      if 0<=nx<=w-1 and 0<=ny<=h-1 and s[ny][nx]=="." and (maze[ny][nx]==-1 or maze[ny][nx]>maze[y][x]):
        qu.appendleft((nx,ny))
        maze[ny][nx]=maze[y][x]
  return maze
    
maze = bfs()
print(maze[dh-1][dw-1])

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
            ans[j][i]=(ans[y][x]+1)
            qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]
ans[ch-1][cw-1]=0

qu = deque([])
qu.append((cw-1,ch-1))
while qu:
  x,y=qu.popleft()

  for i in range(max(x-2,0),min(x+3,w)):
    for j in range(max(y-2,0),min(y+3,h)):
      if (x==i and y==j):
        continue
      if maze[j][i]=="." and (ans[j][i]>ans[y][x] or ans[j][i]==-1):
        if (x==i and y==j+1) or (x==i+1 and y==j) or (x==i-1 and y==j) or (x==i and y==j-1):
          qu.appendleft((i,j))
          ans[j][i] = ans[y][x]
        elif ans[j][i]>ans[y][x]+1 or ans[j][i]==-1:
          ans[j][i]=(ans[y][x]+1)
          qu.appendleft((i,j))

print(ans[dh-1][dw-1])

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0

qu = deque([])
qu.append([cw-1,ch-1])
while qu:
  zahyou=qu.popleft()
  x=zahyou[0]
  y=zahyou[1]
  count=[0,0,0,0]
  count2=0
  for i in range(4):
    if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
      if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
        qu.append([x+dx[i],y+dy[i]])
        ans[y+dy[i]][x+dx[i]] = ans[y][x]
        count[i]=1
        count2+=1
  if count2<3 or (count==[1,0,0,1] or count==[1,1,0,0] or count==[0,1,1,0] or count==[0,0,1,1]):
    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
            ans[j][i]=(ans[y][x]+1)
            qu.append([i,j])

print(ans[dh-1][dw-1])
  




Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=[0,0,0,0]
    count2=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count[i]=1
          count2+=1
    if count2<3 or (count==[1,0,0,1] or count==[1,1,0,0] or count==[0,1,1,0] or count==[0,0,1,1]):
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
  




Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Runtime Error):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=[0,0,0,0]
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count[i]=1
    if count<3 or (count==[1,0,0,1] or count==[1,1,0,0] or count==[0,1,1,0] or count==[0,0,1,1]):
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count<3:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]
ans[ch-1][cw-1]=0
count=0

def bfs(ans):
  qu = deque([])
  qu.append((cw-1,ch-1))
  while qu:
    x,y=qu.popleft()

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if (x==i and y==j):
          continue
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x] or ans[j][i]==-1):
            if (x==i and y==j+1) or (x==i+1 and y==j) or (x==i-1 and y==j) or (x==i and y==j-1):
              qu.appendleft((i,j))
              ans[j][i] = ans[y][x]
            elif ans[j][i]>=ans[y][x]+1 or ans[j][i]==-1:
              ans[j][i]=(ans[y][x]+1)
              qu.appendleft((i,j))

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]
ans[ch-1][cw-1]=0
count=0

def bfs(ans):
  qu = deque([])
  qu.append((cw-1,ch-1))
  while qu:
    x,y=qu.popleft()

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if (x==i and y==j):
          continue
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x] or ans[j][i]==-1):
            if (x==i and y==j+1) or (x==i+1 and y==j) or (x==i-1 and y==j) or (x==i and y==j-1):
              qu.appendleft((i,j))
              ans[j][i] = ans[y][x]
            elif ans[j][i]>ans[y][x]+1 or ans[j][i]==-1:
              ans[j][i]=(ans[y][x]+1)
              qu.appendleft((i,j))

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]
ans[ch-1][cw-1]=0
dx=[0,1,0,-1]
dy=[1,0,-1,0]
count=0

def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if (x==i and y==j):
          continue
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x] or ans[j][i]==-1):
            if (x==i and y==j+1) or (x==i+1 and y==j) or (x==i-1 and y==j) or (x==i and y==j-1):
              qu.append([i,j])
              ans[j][i] = ans[y][x]
            elif ans[j][i]>ans[y][x]+1 or ans[j][i]==-1:
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]
count=0
def niko(x,y,k,ans):
  for i in range(x-2,x+2):
    for j in range(y-2,y+2):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>k or ans[j][i]==-1):
          ans[j][i]=k
  return ans
ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if (x==i and y==j):
          continue
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x] or ans[j][i]==-1):
            if (x==i and y==j+1) or (x==i+1 and y==j) or (x==i-1 and y==j) or (x==i and y==j-1):
              qu.append([i,j])
              ans[j][i] = ans[y][x]
            elif ans[j][i]>ans[y][x]+1 or ans[j][i]==-1:
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Runtime Error):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]
count=0
#niko(x,y,ans[y][x]+1)とする。
def niko(x,y,k,ans):
  for i in range(x-2,x+2):
    for j in range(y-2,y+2):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>k or ans[j][i]==-1):
          ans[j][i]=k
  return ans
ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if 0<=i<w and 0<=j<h:
          if (x==i and y==j+1) or (x==i+1 and y==j) or (x==i-1 and y==j) or (x==i and y==j-1) or (x==i and y==j):
            if maze[j][i]=="." and (ans[j][i]>ans[y][x] or ans[j][i]==-1):
              qu.append([x+dx[i],y+dy[i]])
              ans[y+dy[i]][x+dx[i]] = ans[y][x]
          elif maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
            ans[j][i]=(ans[y][x]+1)
            qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  



Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Runtime Error):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

def bfs(ans):
  ans[ch-1][cw-1]=0
  qu = deque([])
  qu.append([cw-1,ch-1])
  for i in range(cw-1-2,cw-1+3):
    for j in range(ch-1-2,ch-1+3):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>ans[ch][cw]+1 or ans[j][i]==-1):
          ans[j][i]=(ans[ch][cw]+1)
          qu.append([i,j])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    if x==dw-1 and y==dh-1:
      break
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h and maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):

        qu.append([x+dx[i],y+dy[i]])
        ans[y+dy[i]][x+dx[i]] = ans[y][x]
        if i==0:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]+2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]+2])
              ans[y+dy[i]+2][x+dx[i]+j] = ans[y][x]+1
        elif i==2:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]-2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]-2])
              ans[y+dy[i]-2][x+dx[i]+j] = ans[y][x]+1
              
        elif i==1:
          for j in range(-2,3):
            if 0 <= x+dx[i]+2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]+j][x+dx[i]+2]=="." and (ans[y+dy[i]+j][x+dx[i]+2]>ans[y][x]+1 or ans[y+dy[i]+j][x+dx[i]+2]==-1):
              qu.append([x+dx[i]+2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]+2] = ans[y][x]+1
        else:
          for j in range(-2,3):
            if 0 <= x+dx[i]-2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]+j][x+dx[i]-2]=="." and (ans[y+dy[i]-j][x+dx[i]-2]>ans[y][x]+1 or ans[y+dy[i]-j][x+dx[i]-2]==-1):
              qu.append([x+dx[i]-2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]-2] = ans[y][x]+1


bfs(ans)
print(ans[dh-1][dw-1])
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Runtime Error):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

def bfs(ans):
  ans[ch-1][cw-1]=0
  qu = deque([])
  qu.append([cw-1,ch-1])
  for i in range(cw-1-2,cw-1+3):
    for j in range(ch-1-2,ch-1+3):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>ans[ch][cw]+1 or ans[j][i]==-1):
          ans[j][i]=(ans[ch][cw]+1)
          qu.append([i,j])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    if x==dw-1 and y==dh-1:
      break
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h and maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):

        qu.append([x+dx[i],y+dy[i]])
        ans[y+dy[i]][x+dx[i]] = ans[y][x]
        if i==3:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]+2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]+2])
              ans[y+dy[i]+2][x+dx[i]+j] = ans[y][x]+1
        elif i==1:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]-2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]-2])
              ans[y+dy[i]-2][x+dx[i]+j] = ans[y][x]+1
              
        elif i==0:
          for j in range(-2,3):
            if 0 <= x+dx[i]+2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]+2] = ans[y][x]+1
        else:
          for j in range(-2,3):
            if 0 <= x+dx[i]-2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]+j][x+dx[i]]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+j-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]-2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]-2] = ans[y][x]+1


bfs(ans)
print(ans[dh-1][dw-1])
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Runtime Error):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

def bfs(ans):
  ans[ch-1][cw-1]=0
  qu = deque([])
  qu.append([cw-1,ch-1])
  for i in range(cw-1-2,cw-1+3):
    for j in range(ch-1-2,ch-1+3):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>ans[ch][cw]+1 or ans[j][i]==-1):
          ans[j][i]=(ans[ch][cw]+1)
          qu.append([i,j])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    if x==dw-1 and y==dh-1:
      break
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h and maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):

        qu.append([x+dx[i],y+dy[i]])
        ans[y+dy[i]][x+dx[i]] = ans[y][x]
        if i==0:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]+2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]+2])
              ans[y+dy[i]+2][x+dx[i]+j] = ans[y][x]+1
        elif i==2:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]-2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]-2])
              ans[y+dy[i]-2][x+dx[i]+j] = ans[y][x]+1
              
        elif i==1:
          for j in range(-2,3):
            if 0 <= x+dx[i]+2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]+2] = ans[y][x]+1
        else:
          for j in range(-2,3):
            if 0 <= x+dx[i]-2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]+j][x+dx[i]]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+j-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]-2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]-2] = ans[y][x]+1


bfs(ans)
print(ans[dh-1][dw-1])
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Runtime Error):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    if x==dw-1 and y==dh-1:
      break
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h and maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):

        qu.append([x+dx[i],y+dy[i]])
        ans[y+dy[i]][x+dx[i]] = ans[y][x]
        if i==0:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]+2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]+2])
              ans[y+dy[i]+2][x+dx[i]+j] = ans[y][x]+1
        elif i==2:
          for j in range(-2,3):
            if 0 <= x+dx[i]+j < w and 0 <= y+dy[i]-2 < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+j,y+dy[i]-2])
              ans[y+dy[i]-2][x+dx[i]+j] = ans[y][x]+1
              
        elif i==1:
          for j in range(-2,3):
            if 0 <= x+dx[i]+2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]][x+dx[i]+j]=="." and (ans[y+dy[i]+2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]+2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]+2] = ans[y][x]+1
        else:
          for j in range(-2,3):
            if 0 <= x+dx[i]-2 < w and 0 <= y+dy[i]+j < h and maze[y+dy[i]+j][x+dx[i]]=="." and (ans[y+dy[i]-2][x+dx[i]+j]>ans[y][x]+1 or ans[y+dy[i]+j-2][x+dx[i]+j]==-1):
              qu.append([x+dx[i]-2,y+dy[i]+j])
              ans[y+dy[i]+j][x+dx[i]-2] = ans[y][x]+1


bfs(ans)
print(ans[dh-1][dw-1])
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
            ans[j][i]=(ans[y][x]+1)
            qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]
count=0
#niko(x,y,ans[y][x]+1)とする。
def niko(x,y,k,ans):
  for i in range(x-2,x+2):
    for j in range(y-2,y+2):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>k or ans[j][i]==-1):
          ans[j][i]=k
  return ans
ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
            ans[j][i]=(ans[y][x]+1)
            qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]
count=0
#niko(x,y,ans[y][x]+1)とする。
def niko(x,y,k,ans):
  for i in range(x-2,x+2):
    for j in range(y-2,y+2):
      if 0<=i<w and 0<=j<h:
        if maze[j][i]=="." and (ans[j][i]>k or ans[j][i]==-1):
          ans[j][i]=k
  return ans
ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.append([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]

    for i in range(x-2,x+3):
      for j in range(y-2,y+3):
        if 0<=i<w and 0<=j<h:
          if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
            ans[j][i]=(ans[y][x]+1)
            qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])
#for i in ans:
#  print(*i)
  

Fixed submission:
from collections import deque
h,w=map(int,input().split())
ch,cw=map(int,input().split())
dh,dw=map(int,input().split())

maze = [list(input()) for i in range(h)]
ans = [[-1]*w for i in range(h)]

dx=[0,1,0,-1]
dy=[1,0,-1,0]

ans[ch-1][cw-1]=0
def bfs(ans):
  qu = deque([])
  qu.append([cw-1,ch-1])
  while qu:
    zahyou=qu.popleft()
    x=zahyou[0]
    y=zahyou[1]
    count=0
    for i in range(4):
      if 0 <= x+dx[i] < w and 0 <= y+dy[i] < h:
        if maze[y+dy[i]][x+dx[i]]=="." and (ans[y+dy[i]][x+dx[i]]>ans[y][x] or ans[y+dy[i]][x+dx[i]]==-1):
          qu.appendleft([x+dx[i],y+dy[i]])
          ans[y+dy[i]][x+dx[i]] = ans[y][x]
          count+=1
    if count!=4:
      for i in range(x-2,x+3):
        for j in range(y-2,y+3):
          if 0<=i<w and 0<=j<h:
            if maze[j][i]=="." and (ans[j][i]>ans[y][x]+1 or ans[j][i]==-1):
              ans[j][i]=(ans[y][x]+1)
              qu.append([i,j])

bfs(ans)
print(ans[dh-1][dw-1])