poj 1321 棋盘问题

深度优先搜索

代码：

#include <iostream>#include <cstring>using namespace std;int n,k;char array[10][10];    //to record the chessboardbool visited[10];      //to record each line's statusint ans ;int sum ;void dfs(int d,int sum){    //d represent the line, sum represent the chess number in the chessboardif(sum == k){ans++;return;}if(d == n+1)     return;for(int j=1;j<=n;j++)  // start from the dth rowif(!visited[j] && array[d][j] == '#'){visited[j] = true;dfs(d+1,sum+1);visited[j] = false;}dfs(d+1,sum);     //start from the (d+1)th row}int main(){while(cin>>n>>k && (n!=-1) && (k!=-1)){ans = 0,sum=0;memset(visited,false,sizeof(visited));for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)cin>>array[i][j];dfs(1,0);cout<<ans<<endl;}return 0;}