Buggy python submission (verdict: Runtime Error):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
d=[I:=h*w]*I
m+=d,
d[a]=1
for s in(q:=[a:=~w+a*w+b]):
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j;p=d[s]+1
   if'.'<m[i][j]or d[t]<p:break
   if d[t]>p:q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
d=[I:=h*w]*I
m+=d,
q=[a:=~w+a*w+b]
d[a]=1
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j;p=d[s]+1
   if'.'<m[i][j]or d[t]<p:break
   if d[t]>p:q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
d=[I:=h*w]*I
m+=d,
q=[a:=~w+a*w+b]
d[a]=1
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if'.'!=m[i][j]or(p:=[s]+1)>d[t]:break
   if d[t]>p:q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j;p=d[s]+1
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<p:break
   if d[t]=>p:q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j;p=d[s]+1
   if(h>i>-1<j<w)-1or'.'<m[i][j]:break
   if d[t]>=p:q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j;p=d[s]+1
   if(h>i>-1<j<w)-1or'.'<m[i][j]:break
   if d[t]>p:q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j;p=d[s]+1
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<p:break
   q+=t,;d[t]=p
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if~d[t]-I:q+=t,;d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if~d[t]-I:q+=t,;d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if~d[t]-I:q+=t,;d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if~d[t]-I:q+=t,;d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
I=h*w
d=[I]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if~d[t]-I:q+=t,
   d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
d=[I:=h*w]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if d[t]==I:q+=t,;d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
h,a,*m=open(0)
h,w,k,a,b,f,g=map(int,(h+a).split())
d=[I:=h*w]*I
a=~w+a*w+b
d[a]=1
q=[a]
for s in q:
 for y,x in(1,0),(-1,0),(0,1),(0,-1):
  for z in range(k):
   i,j=s//w+y*~z,s%w+x*~z;t=i*w+j
   if(h>i>-1<j<w)-1or'.'<m[i][j]or d[t]<=d[s]:break
   if d[t]==I:q+=t,;d[t]=d[s]+1
print(d[~w+f*w+g]%I-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
from collections import*
z,v,a,c=input,range,print,split
h,w,k=map(int,z().c());r,s,t,u=map(lambda x:int(x)-1,z().c())
b=[z()for _ in v(h)];l=[[-1]*w for _ in v(h)];l[r][s]=0
d=deque([(r,s)])
while d:
  x,y=d.popleft();j=l[x][y]
  if(x==t)&(y==u):exit(a(j))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      p,q=x+e*i,y+f*i
      if not((0<=p<h)&(0<=q<w))or b[p][q]=="@" or 0<=l[p][q]<=j:break
      if l[p][q]<0:d+=[(p,q)];l[p][q]=j+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
from collections import*
z,v,a,c=input,range,print,split
h,w,k=map(int,z().c());r,s,t,u=map(lambda x:int(x)-1,z().c())
b=[z()for _ in v(h)];l=[[-1]*w for _ in v(h)];l[r][s]=0
d=deque([(r,s)])
while d:
  x,y=d.popleft();j=l[x][y]
  if(x==t)&(y==u):exit(a(j))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      p,q=x+e*i,y+f*i
      if not((0<=p<h)&(0<=q<w))or b[p][q]=="@" or 0<=l[p][q]<=j:break
      if l[p][q]<0:d+=[(p,q)];l[p][q]=j+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
from collections import*
z,v,a=input,range,print
h,w,k=map(int,z().split());r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)];l=[[-1]*w for _ in v(h)];l[r][s]=0
d=deque([(r,s)])
while d:
  x,y=d.popleft();j=l[x][y]
  if(x==t)&(y==u):exit(a(j))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      p,q=x+e*i,y+f*i
      if not((0<=p<h)&(0<=q<w))or b[p][q]=="@" or 0<=(c:=l[p][q])<=j:break
      if c<0:d+=[(p,q)];l[p][q]=j+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
from collections import*
z,v,a=input,range,print
h,w,k=map(int,z().split());r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)];l=[[-1]*w for _ in v(h)];l[r][s]=0
d=deque([(r,s)])
while d:
  x,y=d.popleft();j=l[x][y]
  if(x==t)&(y==u):exit(a(j))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      p,q=x+e*i,y+f*i;c=l[p][q]
      if not((0<=p<h)&(0<=q<w))or b[p][q]=="@" or 0<=v<=j:break
      if c<0:d+=[(p,q)];l[p][q]=j+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
from collections import*
z,v,a=input,range,print
h,w,k=map(int,z().split());r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)];l=[[-1]*w for _ in v(h)];l[r][s]=0
d=deque([(r,s)])
while d:x,y=d.popleft()
  if(x==t)&(y==u):exit(a(l[x][y]))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      p,q=x+e*i,y+f*i
      if not((0<=p<h)&(0<=q<w))or b[p][q]=="@" or 0<=l[p][q]<=l[x][y]:break
      if l[p][q]<0:d+=[(p,q)];l[p][q]=l[x][y]+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
z,v,a=input,range,print
h,w,k=map(int,z().split())
r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)]
l=[[-1]*w for _ in v(h)]
l[r][s]=0
from collections import*
d=deque([(r,s)])
while d:
  x,y=d.popleft()
  if(x==t)&(y==u):exit(a(l[x][y]))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      p,q=x+e*i,y+f*i
      if not((0<=p<h)&(0<=q<w))or b[p][q]=="@" or 0<=l[p][q]<=l[x][y]:break
      d+=[(p,q)];l[p][q]=l[x][y]+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
z,v,a=input,range,print
h,w,k=map(int,z().split())
r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)]
l=[[-1]*w for _ in v(h)]
l[r][s]=0
from collections import*
d=deque([(r,s)])
while d:
  x,y=d.popleft()
  if(x==t)&(y==u):exit(a(l[x][y]))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      if not((0<=(p:=(x+e*i))<h)&(0<=(q:=(y+f*i))<w))or b[p][q]=="@" or 0<=l[p][q]<=l[x][y]:break
      if l[p][q]==-1:d+=[(p,q)];l[p][q]=l[x][y]+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
z,v,a=input,range,print
h,w,k=map(int,z().split())
r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)]
l=[[-1]*w for _ in v(h)]
l[r][s]=0
from collections import*
d=deque([(r,s)])
while d:
  x,y=d.popleft()
  if(x==t)&(y==u):exit(a(l[x][y]))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      if not((0<=p:=(x+e*i)<h)&(0<=q:=(y+f*i)<w))or b[p][q]=="@" or 0<=l[p][q]<=l[x][y]:break
      if l[p][q]==-1:d+=[(p,q)];l[p][q]=l[x][y]+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
z,v,a=input,range,print
h,w,k=map(int,z().split())
r,s,t,u=map(lambda x:int(x)-1,z().split())
b=[z()for _ in v(h)]
l=[[-1]*w for _ in v(h)]
l[r][s]=0
from collections import*
d=deque([(r,s)])
while d:
  x,y=d.popleft()
  if(x==t)&(y==u):exit(a(l[x][y]))
  for e,f in[[1,0],[-1,0],[0,-1],[0,1]]:
    for i in v(1,k+1):
      if not((0<=(p:=x+e*i)<h)&(0<=(q:=y+f*i)<w))or b[p][q]=="@" or 0<=l[p][q]<=l[x][y]:break
      if l[p][q]==-1:d+=[(p,q)];l[p][q]=l[x][y]+1
a(-1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque([[x1-1,y1-1]])
dp[x1-1][y1-1]=0
def bfs(d):
    global dp,now
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub+=[[x,y+j,d]]
                cand.add((x,y+j))
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub+=[[x,y-j,d]]
                cand.add((x,y-j))
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub+=[[x+j,y,d]]
                cand.add((x+j,y))
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub+=[[x-j,y,d]]
                cand.add((x-j,y))
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now+=[i]
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque([[x1-1,y1-1]])
dp[x1-1][y1-1]=0
def bfs(d):
    global dp,now
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub+=[[x,y+j,d]]
                cand+=[(x,y+j)]
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub+=[[x,y-j,d]]
                cand+=[(x,y-j)]
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub+=[[x+j,y,d]]
                cand+=[(x+j,y)]
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub+=[[x-j,y,d]]
                cand+=[(x-j,y)]
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now+=[i]
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque([[x1-1,y1-1]])
dp[x1-1][y1-1]=0
def bfs(d):
    global dp,now
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub+=[[x,y+j,d]]
                cand+=[(x,y+j)]
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub+=[[x,y-j,d]]
                cand+=[(x,y-j)]
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub+=[[x+j,y,d]]
                cand.+=[(x+j,y)]
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub+=[[x-j,y,d]]
                cand+=[(x-j,y)]
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now+=[i]
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque([x1-1,y1-1])
dp[x1-1][y1-1]=0
def bfs(d):
    global dp,now
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                cand.add((x,y+j))
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                cand.add((x,y-j))
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                cand.add((x+j,y))
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                cand.add((x-j,y))
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x2-1,y2-1])
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp[x][y+j]=d
                now.append([x,y+j])
            if dp[x][y+j]==-1:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp[x][y-j]=d
                now.append([x,y-j])
            if dp[x][y-j]==-1:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp[x+j][y]=d
                now.append([x+j,y])
            if dp[x+j][y]==-1:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp[x-j][y]=d
                now.append([x-j,y])
            if dp[x-j][y]==-1:
                break
    bfs(d+1)
bfs(1)
print(dp[x1-1][y1-1] if dp[x1-1][y1-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=10000000
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp[x][y+j]=d
                now.append([x,y+j])
            if dp[x][y+j]==-1:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp[x][y-j]=d
                now.append([x,y-j])
            if dp[x][y-j]==-1:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp[x+j][y]=d
                now.append([x+j,y])
            if dp[x+j][y]==-1:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp[x-j][y]=d
                now.append([x-j,y])
            if dp[x-j][y]==-1:
                break
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp[x][y+j]=d
                now.append([x,y+j])
            if dp[x][y+j]==-1:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp[x][y-j]=d
                now.append([x,y-j])
            if dp[x][y-j]==-1:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp[x+j][y]=d
                now.append([x+j,y])
            if dp[x+j][y]==-1:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp[x-j][y]=d
                now.append([x-j,y])
            if dp[x-j][y]==-1:
                break
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    if dp[x2-1][y2-1]!=inf and dp[x2-1][y2-1]!=-1:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp[x][y+j]=d
                now.append([x,y+j])
            if dp[x][y+j]==-1:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp[x][y-j]=d
                now.append([x,y-j])
            if dp[x][y-j]==-1:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp[x+j][y]=d
                now.append([x+j,y])
            if dp[x+j][y]==-1:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp[x-j][y]=d
                now.append([x-j,y])
            if dp[x-j][y]==-1:
                break
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,dp,now
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp[x][y+j]=d
                now.append([x,y+j])
            if dp[x][y+j]==-1:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp[x][y-j]=d
                now.append([x,y-j])
            if dp[x][y-j]==-1:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp[x+j][y]=d
                now.append([x+j,y])
            if dp[x+j][y]==-1:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp[x-j][y]=d
                now.append([x-j,y])
            if dp[x-j][y]==-1:
                break
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf]*w for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,x1,y1,x2,y2,c,dp,now
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if c[x][y+j]==".":
                if dp[x][y+j]==inf:
                    dp[x][y+j]=d
                    now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if c[x][y-j]==".":
                if dp[x][y-j]==inf:
                    dp[x][y-j]=d
                    now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if c[x+j][y]==".":
                if dp[x+j][y]==inf:
                    dp[x+j][y]=d
                    now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if c[x-j][y]==".":
                if dp[x-j][y]==inf:
                    dp[x-j][y]=d
                    now.append([x-j,y])
            else:
                break
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Runtime Error):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf]*w for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,x1,y1,x2,y2,c,dp,now
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,max(k+1,w-y)):
            if c[x][y+j]==".":
                if dp[x][y+j]==inf:
                    dp[x][y+j]=d
                    now.append([x,y+j])
            else:
                break
        for j in range(1,max(k+1,y+1)):
            if c[x][y-j]==".":
                if dp[x][y-j]==inf:
                    dp[x][y-j]=d
                    now.append([x,y-j])
            else:
                break
        for j in range(1,max(k+1,h-x)):
            if c[x+j][y]==".":
                if dp[x+j][y]==inf:
                    dp[x+j][y]=d
                    now.append([x+j,y])
            else:
                break
        for j in range(1,max(k+1,x+1)):
            if c[x-j][y]==".":
                if dp[x-j][y]==inf:
                    dp[x-j][y]=d
                    now.append([x-j,y])
            else:
                break
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf]*w for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,x1,y1,x2,y2,c,dp,now
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,k+1):
            if y+j>=w:
                break
            if c[x][y+j]==".":
                if dp[x][y+j]==inf:
                    dp[x][y+j]=d
                    now.append([x,y+j])
            else:
                break
        for j in range(1,k+1):
            if y-j<0:
                break
            if c[x][y-j]==".":
                if dp[x][y-j]==inf:
                    dp[x][y-j]=d
                    now.append([x,y-j])
            else:
                break
        for j in range(1,k+1):
            if x+j>=h:
                break
            if c[x+j][y]==".":
                if dp[x+j][y]==inf:
                    dp[x+j][y]=d
                    now.append([x+j,y])
            else:
                break
        for j in range(1,k+1):
            if x-j<0:
                break
            if c[x-j][y]==".":
                if dp[x-j][y]==inf:
                    dp[x-j][y]=d
                    now.append([x-j,y])
            else:
                break
    bfs(d+1)
bfs(1)
#print(dp)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf]*w for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
def bfs(d):
    global h,w,k,x1,y1,x2,y2,c,dp,now
    l=len(now)
    if l==0:
        return
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,k+1):
            if y+j>=w:
                break
            if c[x][y+j]==".":
                if dp[x][y+j]==inf:
                    dp[x][y+j]=d
                    now.append([x,y+j])
            else:
                break
        for j in range(1,k+1):
            if y-j<0:
                break
            if c[x][y-j]==".":
                if dp[x][y-j]==inf:
                    dp[x][y-j]=d
                    now.append([x,y-j])
            else:
                break
        for j in range(1,k+1):
            if x+j>=h:
                break
            if c[x+j][y]==".":
                if dp[x+j][y]==inf:
                    dp[x+j][y]=d
                    now.append([x+j,y])
            else:
                break
        for j in range(1,k+1):
            if x-j<0:
                break
            if c[x-j][y]==".":
                if dp[x-j][y]==inf:
                    dp[x-j][y]=d
                    now.append([x-j,y])
            else:
                break
    bfs(d+1)
bfs(1)
#print(dp)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)

Fixed submission:
import sys
inf=1000002
sys.setrecursionlimit(inf)
from collections import deque
h,w,k=map(int,input().split())
x1,y1,x2,y2=map(int,input().split())
c=[input() for i in range(h)]
dp=[[inf if c[i][j]=="." else -1 for j in range(w)] for i in range(h)]
now=deque()
now.append([x1-1,y1-1])
dp[x1-1][y1-1]=0
#kの更新が遅い
def bfs(d):
    global h,w,k,dp,now,x2,y2
    l=len(now)
    if l==0:
        return
    dp_sub=deque()
    cand=set()
    for i in range(l):
        x,y=now.popleft()
        for j in range(1,min(k+1,w-y)):
            if dp[x][y+j]==inf:
                dp_sub.append([x,y+j,d])
                #dp[x][y+j]=d
                cand.add((x,y+j))
                #now.append([x,y+j])
            else:
                break
        for j in range(1,min(k+1,y+1)):
            if dp[x][y-j]==inf:
                dp_sub.append([x,y-j,d])
                #dp[x][y-j]=d
                cand.add((x,y-j))
                #now.append([x,y-j])
            else:
                break
        for j in range(1,min(k+1,h-x)):
            if dp[x+j][y]==inf:
                dp_sub.append([x+j,y,d])
                #dp[x+j][y]=d
                cand.add((x+j,y))
                #now.append([x+j,y])
            else:
                break
        for j in range(1,min(k+1,x+1)):
            if dp[x-j][y]==inf:
                dp_sub.append([x-j,y,d])
                #dp[x-j][y]=d
                cand.add((x-j,y))
                #now.append([x-j,y])
            else:
                break
    while dp_sub!=deque([]):
        e=dp_sub.popleft()
        dp[e[0]][e[1]]=e[2]
    for i in cand:
        now.append(i)
    bfs(d+1)
bfs(1)
print(dp[x2-1][y2-1] if dp[x2-1][y2-1]!=inf else -1)