hdu 1162 Eddy's picture（最小生成树，基础）

 

题目

 

 

#define  _CRT_SECURE_NO_WARNINGS

#include <stdio.h>
#include<string.h>
#include <malloc.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
#include<math.h>
using namespace std;

#define M 110
#define inf 999999999
double mat[M][M];
struct tt
{
    double x,y;
}dian[M];

double prim(int n,int sta)
{
    double minn,sum=0,dis[M];
    int mark[M],i,j,flag;
    for(i=0;i<n;i++)
    {
        dis[i]=mat[sta][i];
        mark[i]=0;
    }
    mark[sta]=1;
    for(i=1;i<n;i++)
    {
        minn=inf;
        for(j=0;j<n;j++)
        {
            if(mark[j]==0&&dis[j]<minn)
            {
                minn=dis[j];
                flag=j;
            }
        }
        mark[flag]=1;
        sum+=dis[flag];
        for(j=0;j<n;j++)
        {
            if(dis[j]>mat[flag][j])
                dis[j]=mat[flag][j];
        }
    }
    return sum;
}

int main()
{
    int n,m,i,j;
    while(scanf("%d",&n)!=EOF)
    {
        for(i=0;i<n;i++)
        {
            scanf("%lf%lf",&dian[i].x,&dian[i].y);
            for(j=0;j<i;j++)
            {
                mat[i][j]=mat[j][i]=sqrt((dian[i].x-dian[j].x)*(dian[i].x-dian[j].x)+(dian[i].y-dian[j].y)*(dian[i].y-dian[j].y));
            }
        }
        printf("%.2lf\n",prim(n,0));
    }
    return 0;
}