POJ 1321（DP初步_I题）解题报告

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
#include<stack>
#include<bitset>
#include<cstdlib>
#include<cmath>
#include<set>
#include<list>
#include<deque>
#include<map>
#include<queue>
using namespace std;
typedef long long ll;
const double PI = acos(-1.0);
const double eps = 1e-6;
const int MAXN =10+10;
int n,k;  
char chess[MAXN][MAXN];  
int row[MAXN];  
int col[MAXN];  
int sum;  
void dfs(int step,int hang)  
{  
    if(step==k)   
    {  
        sum++;  
        return ;  
    }  
    for(int i=hang;i<n;i++)  
    {  
        for(int j=0;j<n;j++)  
        {  
            if(row[i]==1||col[j]==1||chess[i][j]!=‘#‘) continue;  
            else  
            {  
                row[i]=col[j]=1;  
                dfs(step+1,i);   
                row[i]=col[j]=0;  
            }  
        }  
    }  
}   
  
int main()  
{  
    while(scanf("%d%d",&n,&k)&&(n!=-1&&k!=-1)){  
        memset(chess,0,sizeof(chess));  
        memset(row,0,sizeof(row));  
        memset(col,0,sizeof(col));  
        sum=0;    
        for(int i=0;i<n;i++){  
            scanf("%s",&chess[i]);  
        }  
        dfs(0,0);  
        printf("%d\n",sum);   
    }   
    return 0;  
}