P1433 吃奶酪

#include"stdafx.h"
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<cmath>
#include<map>
#include<algorithm>
#define INF 0x3f3f3f3f
using namespace std;

int N,vis[20];
double ans=INF;

struct cc{
    double x,y;
}nod[20];

double dis(int a,int b){
    return sqrt((nod[a].x-nod[b].x)*(nod[a].x-nod[b].x)+(nod[a].y-nod[b].y)*(nod[a].y-nod[b].y));
}

void search(int x,int dep,double len){
    if(len>=ans) return;
    if(dep==N){
        ans=min(len,ans);
        return;
    }
    
    for(int i=1;i<=N;i++){
        if(i==x)continue;
        if(!vis[i]){
            vis[i]=1;
            search(i,dep+1,len+dis(x,i));
            vis[i]=0;
        }
    }
    
}

int _tmain(){
//    freopen("01.in","r",stdin);
    scanf("%d",&N);
    for(int i=1;i<=N;i++)cin>>nod[i].x>>nod[i].y;
    search(0,0,0.0);
    printf("%.2lf",ans);
    return 0;
}