还是畅通工程（HDU 1233）

3
1 2 1
1 3 2
2 3 4
4
1 2 1
1 3 4
1 4 1
2 3 3
2 4 2
3 4 5
0

3
5
Huge input, scanf is recommended.

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
struct node
{
    int b,e;
    int w;
} s[10005];
bool cmp(struct node x, struct node y)
{
    return x.w < y.w;
}
int pre[1000];
int Find(int x)
{
    while(x!=pre[x])
    {
        x = pre[x];
    }
    return x;
}
int Merge(int x, int y)
{
    if(Find(x) != Find(y))
    {
        pre[Find(x)] = Find(y);
        return 1;
    }
    return 0;
}
int kruskal(int n, int x)
{
    int ans = 0, num = 0;
    for(int i =0; i <= n; i ++)
    {
        pre[i] = i;
    }
    for(int i =0; i < x; i ++)
    {
        if(Merge(s[i].b, s[i].e) == 1)
        {
            ans += s[i].w;
            num ++;
        }
        if(num == n - 1)break;
    }
    return ans;
}
int main()
{
    int n,x;
    while(~scanf("%d",&n)&&n)
    {
        x = (n*(n -1)) / 2;
        for(int i = 0; i < (n*(n - 1)) / 2; i ++)
        {
            scanf("%d %d %d",&s[i].b, &s[i].e, &s[i].w);
        }
        sort(s,s + x, cmp);
        int ans = kruskal(n,x);
        printf("%d\n",ans);
    }
    return 0;
}