HDU 1233 還是暢通工程

最小生成樹。kruscal算法

#include<stdio.h>
#include<algorithm>
using namespace std;

int root[101];
int N, Q, i, j, a, b, d, t, ans;
struct road
{
    int s;
    int e;
    int d;
} edge[5051];
bool cmp(road a, road b)
{
    return a.d < b.d;
}
int find(int a)
{
    while(a != root[a])
        a = root[a];
    return a;
}
void merge(int a, int b)
{
    a = find(a);
    b = find(b);
    if(a != b)
        root[b] = a;
}
int main()
{
    while(scanf("%d", &N) == 1 && N)
    {
        for(i = 1; i < 101; i++)
            root[i] = i;
        t = 0;
        int m = N*(N-1)/2;
        for(i = 1; i <= m; i++)
        {
            int a, b, c;
            scanf("%d %d %d", &a, &b, &c);
            edge[t].s = a;
            edge[t].e = b;
            edge[t].d = c;
            t++;
        }
        sort(edge, edge+t, cmp);
        ans = 0;
        for(i = 0; i < t; i++)
        {
            if(find(edge[i].s) != find(edge[i].e))
            {
                merge(edge[i].s,edge[i].e);
                ans += edge[i].d;
            }
        }
        printf("%d\n", ans);
    }
}