[kuangbin带你飞]专题一 简单搜索 - A - 棋盘问题

 #include<iostream>
 #include<cstdio>
 #include<string>
 #include<vector>
 #include<cstring>
 using namespace std;
 struct node
 {
     int x;
     int y;
 };
 int n, k, l, ans;
 bool w[], h[];
 vector<node>dot;
 void bfs(int a, int b)
 {
     if(a==k+)
     {
         ans++;
         return;
     }
     for(int i = b; i < l; i++)
     {
         if(w[dot[i].x] || h[dot[i].y])    continue;
         else
         {
             w[dot[i].x] = h[dot[i].y] = true;
             bfs(a+, i+);
             w[dot[i].x] = h[dot[i].y] = false;
         }
     }
     return;
 }
 int main()
 {
 //    freopen("in.in","r",stdin);
     string c;
     node tmp;
     while(cin>>n>>k)
     {
         dot.clear();
         memset(w,,sizeof(w));
         memset(h,,sizeof(h));
         if(n==-)    break;
         for(int i = ; i <= n; i++)
         {
             cin>>c;
             for(int j = ; j <= n; j++)
             {

                 if(c[j-]=='#')
                 {
                     tmp.x = i;
                     tmp.y = j;
                     dot.push_back(tmp);
                 }
             }
         }

         l = dot.size();
         ans = ;
         bfs(,);
         cout<<ans<<endl;
     }
     return ;
 }