题目链接
AC代码
#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
const int manx=1e5+6;
int n,k,ans=0,vis[1005];
char g[1005][1005];
void dfs(int r,int cnt) {
if(cnt==k){
ans++;
return ;
}
for(int i=r;i<n;i++){
for(int j=0;j<n;j++){
if(g[i][j]=='#'&&!vis[j]){
vis[j]=1;
dfs(i+1,cnt+1);//这一行用过了,从下一行开始找
vis[j]=0;
}
}
}
}
int main() {
while(cin>>n>>k&&n!=-1&&k!=-1) {
memset(vis,0,sizeof(vis));
ans=0;
for(int i=0; i<n; i++)cin>>g[i];
dfs(0,0);
cout<<ans<<endl;
}
}
#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
const int manx=1e5+6;
int n,k,ans=0,vis[1005];
char g[1005][1005];
void dfs(int r,int cnt) {
if(cnt==k){
ans++;
return;
}
for(int i=r;i<=n;i++){
for(int j=1;j<=n;j++){
if(g[i][j]=='#'&&!vis[j]){
vis[j]=1;
dfs(i+1,cnt+1);//这一行用过了,从下一行开始找
vis[j]=0;
}
}
}
}
int main() {
while(cin>>n>>k&&n!=-1&&k!=-1) {
memset(vis,0,sizeof(vis));
ans=0;
for(int i=1; i<=n; i++)
for(int j=1; j<=n; j++)cin>>g[i][j];
//for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)cout<<g[i][j];//z这一种写法J是默认从0开始的,要注意
dfs(1,0);
cout<<ans<<endl;
}
}