POJ 1321 棋盘问题 DFS 期末前水一水就好……

#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <typeinfo>
#include <fstream>
typedef long long ll;
using namespace std;
//freopen("D.in","r",stdin);
//freopen("D.out","w",stdout);
#define sspeed ios_base::sync_with_stdio(0);cin.tie(0)
#define maxn 10
const int inf=0x7fffffff;   //无限大
char board[maxn][maxn];
int place[maxn];
int n,k;
int cnt,num;

void dfs(int i)
{
    if(k==num)
    {
        cnt++;
        return;
    }
    if(i>=n)
        return;
    for(int j=0;j<n;j++)
    {
        if(!place[j]&&board[i][j]==‘#‘)
        {
            place[j]=1;
            num++;
            dfs(i+1);
            place[j]=0;
            num--;
        }
    }
    dfs(i+1);
}
int main()
{
    while(cin>>n>>k)
    {
        if(n==-1&&k==-1)
            break;
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<n;j++)
                cin>>board[i][j];
        }
        memset(place,0,sizeof(place));
        cnt=0;
        num=0;
        dfs(0);
        cout<<cnt<<endl;
    }
    return 0;
}