A 棋盘问题

2 1#..#4 4...#..#..#..#...-1 -1Sample Output
2
1
//感觉就是DFS的典型题
#include <cstdio>#include <iostream>#include <cstring>using namespace std;int n,k,ans;char map[12][12];int vis[12];int DFS(int i,int c){	if(c >= k)	{		ans++;		return 0;	}	int x,y;	for(x = i;x < n;x++)	for(y = 0;y < n;y++)	if(!vis[y] && map[x][y]=='#')	{		vis[y]=1;		DFS(x+1,c+1);		vis[y]=0;	}	return 0;	 } int main(){	while(scanf("%d%d",&n,&k) && n!=-1)	{		ans=0;		memset(map,0,sizeof(map));		memset(vis,0,sizeof(vis));		for(int i=0;i<n;i++)		scanf("%s",map[i]);		DFS(0,0);		PRintf("%d/n",ans);	}	return 0;}