POJ 1321 棋盘问题类似八皇后 dfs搜索

#include <iostream>
using namespace std;
char qipan[8][8];
bool col[8];
int m,n,count;
//r为行数，k代表已经填充的棋子数，count代表方案数
void dfs(int r,int k)
{
	if (k == m)
	{
		count++; 
		return;
	}
	if (r > n)
	{
		return;
	}
	for (int i = 0;i < n;i++)
		if ( !col[i] && qipan[r][i] == '#')//若第i列没有放且qipan[r][i] == '#'
		{
			col[i] = 1;
			dfs(r+1,k+1);
			col[i] = 0;
		}
	dfs(r+1,k);
}
int main(){
	while(cin>>n>>m){
		if (n == -1 && m == -1) break;
		count = 0;
		for (int i = 0;i < n;i++)
			for (int j = 0;j < n;j++)
			{
				cin>>qipan[i][j];
			}
		memset(col,false,sizeof(col));
		dfs(0,0);
		cout<<count<<endl;
		}
	return 0;
}