poj 3182 The Grove bfs

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int maxn=5e1+9,inf=1e9;
char a[maxn][maxn],now[maxn][maxn];
int dist[maxn][maxn],d[maxn][maxn],quex[1111111],quey[1111111];
int n,m;
void init()
{
memset(a,0,sizeof(a));
memset(now,0,sizeof(now));
}

void bfs(int x,int y,int dist[maxn][maxn])
{
bool visit[maxn][maxn];
memset(dist,50,sizeof(dist));
memset(visit,0,sizeof(visit));
dist[x][y]=0;
int front=1,end=0;
quex[++end]=x;
quey[end]=y;
visit[x][y]=1;
while(front<=end)
{
int nowx=quex[front],nowy=quey[front++];
int tox,toy;
for(int i=-1;i<=1;i++)
for(int j=-1;j<=1;j++)
{
tox=nowx+i;
toy=nowy+j;
if(tox>n||tox<1) continue;
if(toy>m||toy<1) continue;
if(now[tox][toy]=='X') continue;
if(!visit[tox][toy])
{
visit[tox][toy]=1;
dist[tox][toy]=dist[nowx][nowy]+1;
quex[++end]=tox;
quey[end]=toy;
}
}
}
}

int main()
{
//    freopen("in.txt","r",stdin);
while(scanf("%d %d",&n,&m)!=EOF)
{
init();
int sx,sy,lowx,lowy;
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
{
char tmp;
tmp=getchar();
if(tmp==' '||tmp=='\n')  j--;
else a[i][j]=tmp;
if(tmp=='*') sx=i,sy=j;
}
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
if(a[i][j]=='X')
{
lowx=i;
lowy=j;
i=n+1;
break;
}
for(int i=1;i<=n;i++) strcpy(now[i]+1,a[i]+1);
for(int i=lowx;i>=1;i--)
now[i][lowy-1]='X';
bfs(sx,sy,dist);

int upx=lowx,upy;
for(int j=m;j>=1;j--)
if(a[upx][j]=='X')
{
upy=j;
break;
}

for(int i=1;i<=n;i++) strcpy(now[i]+1,a[i]+1);
for(int i=upx;i>=1;i--)
now[i][upy+1]='X';

int ans=inf;
for(int i=lowx-1;i>=1;i--)
{
bfs(i,lowy,d);
ans=min(ans,dist[i][lowy]+d[sx][sy]);
}
cout<<ans<<endl;
}
return 0;
}