POJ_1979_Red and Black

//简单的广度优先搜索
#include<stdio.h>
#include<string.h>
#include<queue>
using namespace std;
queue<int> q;
char map[25][25],f[25][25];
int di[4][2]={-1,0,1,0,0,-1,0,1};
int w,h;
int isin(int m,int n)
{
if(m>0&&m<=h&&n>0&&n<=w)
return 1;
return 0;
}
int bfs(int m,int n)
{
int num=1;
q.push(m);q.push(n);
f[m]
=1;
while(!q.empty())
{
int a,b,i;a=q.front();q.pop();b=q.front();q.pop();
for(i=0;i<4;i++)
{
int x=a+di[i][0],y=b+di[i][1];
if(isin(x,y)&&map[x][y]=='.'&&!f[x][y])
{
map[x][y]=1;
q.push(x);q.push(y);
num+=bfs(x,y);
}
}
}
return num;
}
int main()
{
while(scanf("%d%d",&w,&h)==2)
{
if(w==0&&h==0)
break;
int i,a,b,j;
memset(f,0,sizeof(f));
for(i=1;i<=h;i++)
{
scanf("%s",map[i]+1);
for(j=1;j<=w;j++)
{
if(map[i][j]=='@')
{
a=i;b=j;
break;
}
}
}
printf("%d/n",bfs(a,b));
}
return 0;
}