学步园

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#include"stdio.h"
#include"math.h"
#define INF 9999999
struct point
{
	double x,y;
}point[202];
int n;
double dis[202][202],b[202][202];
double distant(int i,int j)
{
	return sqrt((point[i].x-point[j].x)*(point[i].x-point[j].x)+(point[i].y-point[j].y)*(point[i].y-(point[j].y)));
}
double dp()
{
	int i,j;
	double temp;
	b[1][2]=dis[1][2];
	for(j=3;j<=n;j++)
	{
		for(i=1;i<=j-2;i++)
			b[i][j]=b[i][j-1]+dis[j-1][j];

		b[j-1][j]=INF;
		for(i=1;i<=j-2;i++)
		{
			temp=b[i][j-1]+dis[i][j];
			if(temp<b[j-1][j])
				b[j-1][j]=temp;
		}
	}
	b[n][n]=b[n-1][n]+dis[n-1][n];
	return b[n][n];
}
int main()
{
	int i,j;
	double ans;
	while(scanf("%d",&n)!=-1)
	{
		for(i=1;i<=n;i++)
			scanf("%lf%lf",&point[i].x,&point[i].y);

		for(j=2;j<=n;j++)
			for(i=1;i<j;i++)
				dis[i][j]=distant(i,j);
		ans=dp();
		printf("%.2f\n",ans);
	}
	return 0;
}