UVA1347 Tour

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define se second
#define fs first
#define ll long long
#define CLR(x) memset(x,0,sizeof x)
#define MC(x,y) memcpy(x,y,sizeof(x))  
#define SZ(x) ((int)(x).size())
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1 
#define INF 1e9
typedef pair<int,int> P;
const double eps=1e-9;
const int maxnnode=11000;
const int maxn=100100;
const int mod=20071027;

pair<double,double> p[55];
double dist[55][55];
double dp[55][55];


int main(){
	int n;
	while(~scanf("%d",&n))
	{
		for(int i=1;i<=n;i++) scanf("%lf%lf",&p[i].fs,&p[i].se);
		sort(p+1,p+n+1);
		for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++) dp[i][j]=INF;
		for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++) dist[i][j]=sqrt((p[i].fs-p[j].fs)*(p[i].fs-p[j].fs)+(p[i].se-p[j].se)*((p[i].se-p[j].se)));
		dp[2][1]=dist[2][1];
		for(int i=3;i<=n;i++)
		{
			for(int j=1;j<i-1;j++) dp[i][j]=min(dp[i][j],dp[i-1][j]+dist[i][i-1]);
			for(int j=1;j<i-1;j++) dp[i][i-1]=min(dp[i][i-1],dp[i-1][j]+dist[i][j]);
		}
		double MIN=INF;
		for(int i=1;i<=n-1;i++) MIN=min(MIN,dp[n][i]+dist[n][i]);
		printf("%.2lf\n",MIN);
	}
}