状态压缩DP P1433吃奶酪

题目

洛谷P1433

代码

#include <iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cstring>
#include<cmath>
using namespace std;
int n;
double ans=1e9;
double a[16],b[16],dp[999999][20];
int vis[16];
double dis(int x,int y){
	double temp=sqrt((a[x]-a[y])*(a[x]-a[y])+(b[x]-b[y])*(b[x]-b[y]));
	return temp;
}
void dfs(int k,int x,double s,int bi){
	if(k==n) {
		ans=min(ans,s);
		return;
	}
	if(s>ans) return;
	for(int i=1;i<=n;i++){
		if(!vis[i]){
			int t=bi+(1<<(i-1));
			if(dp[t][i]<=s+dis(x,i)&&dp[t][i]!=0){
				continue;
			}
			vis[i]=1;
			dp[t][i]=s+dis(x,i);
			dfs(k+1,i,s+dis(x,i),t);
			vis[i]=0;
		}
	}
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i]>>b[i];
	}
	dfs(0,0,0,0);
	printf("%.2f",ans);
  return 0;
}




//  freopen("testdata.in", "r", stdin);