View Code of Problem 450

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <stack>
#include <queue>
#include <algorithm>
#include <string>

const int inf = (1<<31)-1;
const int MAXN = 1e1;
using namespace std;

int n,m;
char G[MAXN][MAXN];
int row[MAXN],col[MAXN],num[MAXN];
int sum;

void dfs(int x,int t){
    if(t==m-1){
        sum++;
        return ;
    }

    for(int i=x+1;i<n;i++){
        if(num[i]+t>=m-1){//剪枝2
            for(int j=0;j<n;j++){
                if(!row[i]&&!col[j]&&G[i][j]=='#'){
                    row[i] = col[j] = 1;
                    //cout<<i<<j<<"debug"<<endl;
                    dfs(x+1,t+1);
                    row[i] = col[j] = 0;
                }
            }
        }
    }
}

int main()
{
    while(scanf("%d%d",&n,&m),n!=-1){
        sum = 0;
        int k =0;
        memset(row,0,sizeof(row));
        memset(col,0,sizeof(col));
        memset(num,0,sizeof(num));
        for(int i=0;i<n;i++){
            scanf("%s",G[i]);
        }
        for(int i=n-1;i>=0;i--){
            for(int j=0;j<n;j++){
                if(G[i][j]=='#'){
                    num[i] = 1;
                    k++;
                }
            }
            num[i] += num[i+1]; //每行下至少还有多少个
        }
        //剪枝1
        if(k<m||num[0]<m){
            cout<<0<<endl;
            continue;
        }
      /*  for(int i=0;i<n;i++){
            printf("%s\n",G[i]);
        }*/
        for(int i=0;i<n-m+1;i++){
            if(num[i]>=m){
                for(int j=0;j<n;j++){
                    if(G[i][j]=='#'){
                        row[i] = col[j] = 1;
                        dfs(i,0);
                        row[i] = col[j] = 0;
                    }
                }
            }else{break;}
        }
        cout<<sum<<endl;
    }
    //cout << "Hello world!" << endl;
    return 0;
}