HDU1233——还是通常工程（最小生成树，并查集）

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std; 

int n,s,k;
int par[105];
struct point {
    int x,d,y;
};
point p[5005];

int cmp(point a,point b)
{
     return a.d<b.d;

}
int find(int x) {           
    return par[x] == x ? x : par[x] = find(par[x]);
}

void unite(int x, int y,int i) {
    x = find(x);
    y = find(y);
    if(x == y) return;
    s+=p[i].d;
    k++;
    par[x] = y;
}
int main(){
    while(~scanf("%d",&n)&&n!=0){
        int m=n*(n-1)/2;
        for(int i=0;i<m;i++){
            scanf("%d%d%d",&p[i].x,&p[i].y,&p[i].d);
        }
        s=0;k=0;
        for(int i=1;i<=n;i++){
            par[i]=i;
        }
        sort(p,p+m,cmp);
        for(int i=0;i<m;i++){
            unite(p[i].x,p[i].y,i);
            if(k==n-1)break; 
        }
        printf("%d\n",s);
    }
    return 0;
}