hdu 1233(最小生成树kruskal)

/*
*  最小生成树练手题，采用kruskal求解 
*/
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>

using namespace std;

const int M = 5050;

int p[M];
struct edge {//边节点 
    int a;
    int b;
    int w;
}e[M];


int cmp(const void *a, const void *b) {//按权值从小到大排序 
    return (*(edge *)a).w - (*(edge *)b).w;
}

void init(int vs) {//初始化集合 
    for (int i=1; i<=vs; ++i) p[i] = i;
    return ;
} 

int find(int v) {
    if (p[v] != v) p[v] = find(p[v]);
    return p[v];
}

int join(edge e) {
    int x, y;
    x = find(e.a);
    y = find(e.b);
    if (x != y) {
        p[x] = y;
        return e.w;
    }
    return 0;
}

int kruskal(int es, int vs) {
    int ans = 0;
    init(vs);
    qsort(e, es, sizeof(edge), cmp);
    for (int i=0; i<es; ++i) ans += join(e[i]);
    return ans;
}

int main() {
    int vs;
    while (scanf("%d", &vs), vs) {
        int es = vs * (vs - 1) / 2;
        for (int i=0; i<es; ++i) scanf("%d%d%d", &e[i].a, &e[i].b, &e[i].w);
        int ans = kruskal(es, vs);
        printf ("%d\n", ans);
    }
    return 0;
}