题目链接
http://acm.hdu.edu.cn/showproblem.php?pid=1233
题目很简单（最小生成树）

#include<cstdio>#include<iostream>#include<algorithm>using namespace std;struct node{    int x,y,d;}s[5000];int father[111];int sum;bool cmp(const node &a,const node &b){    return a.d<b.d;}int Find(int x){    if(x==father[x]) return x;    father[x]=Find(father[x]);    return father[x];}void Union(int x,int y,int d){    x=Find(x);    y=Find(y);    if(x!=y)    {        father[x]=y;        sum=sum+d;    }}int main(void){    int n,m,i,j,k,l;    while(scanf("%d",&n)==1&&n)    {        m=n*(n-1)/2;        for(i=0;i<m;i++)        scanf("%d%d%d",&s[i].x,&s[i].y,&s[i].d);        sort(s,s+m,cmp);        for(i=1;i<=n;i++)        father[i]=i;        sum=0;        for(i=0;i<m;i++)        {            Union(s[i].x,s[i].y,s[i].d);        }        printf("%d\n",sum);    }    return 0;}

HDU-1233-还是畅通工程（并查集）