错题记录

#include<bits/stdc++.h>
using namespace std;
int n,ct = 0;
double x[16],y[16],dist[16][16];
double ans;
bool vis[16];
void dfs(int deep,int now,double sum){
	ct++;
	if(ct>=10000000){
		printf("%.2f",ans);
		exit(0);
	}
	if(deep>n){
		if(sum<ans)ans = sum;
		return;
	}
	for(int i = 1;i<=n;i++){
		if(!vis[i]){
			double t = sum+dist[now][i];
			if(t>=ans)continue;
			vis[i] = 1;
			dfs(deep+1,i,t);
			vis[i] = 0;
		}
	}
}
int main(){
	cin>>n;
	ans = 1e6;
	x[0] = 0;
	y[0] = 0;
	for(int i = 1;i<=n;i++){
		cin>>x[i]>>y[i];
	}
	for(int i = 0;i<=n;i++){
		for(int j = 0;j<=n;j++){
			dist[i][j] = sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
		}
	}
	dfs(1,0,0);
	printf("%.2f",ans);
	return 0;
}