杭电 还是畅通工程 （并查集）

   用并查集解决，记下了

 

#include <iostream>#include <cstring>#include <algorithm>using namespace std;#define MAX 5000//  端点序号        权      并查集  排序int u[MAX], v[MAX], w[MAX], p[105], r[MAX];int n, m, sum;int cmp(const int a, const int b){    return w[a]<w[b];}int find(int x){    return p[x]==x?x:find(p[x]);}void Kruskal(){    int i;    for (i=1; i<=n; i++)        p[i] = i;    for (i=1; i<=m; i++)        r[i] = i;    sort(r+1, r+m+1, cmp);    for (i=1; i<=m; i++)    {        int t = r[i];        int x = find(u[t]);        int y = find(v[t]);        if (x!=y)        {            sum += w[t];            p[x] = y;        }    }}int main(){    int i;    while (cin>>n && n)    {        m = n * (n-1) / 2;        sum = 0;        for (i=1; i<=m; i++)        {            scanf("%d%d%d",&u[i], &v[i], &w[i]);               }        Kruskal();        printf("%d\n", sum);    }    return 0;}