poj 1287 Networking

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
struct d
{
    int u,v,w;
}e[10000+5];
int bin[100],n,m;

bool cmp(d a,d b)
{
    return a.w<b.w;
}

int Find(int x)
{
    int s;
    for(s=x;bin[s]>=0;s=bin[s]);

    while(s!=x)
    {
        int t=bin[x];
        bin[x]=s;
        x=t;
    }
    return s;
}

void Union(int x1,int x2)
{
    int f1=Find(x1),f2=Find(x2);
    int t=bin[f1]+bin[f2];
    if(bin[f1]>bin[f2])
    {
        bin[f1]=f2;
        bin[f2]=t;
    }
    else
    {
        bin[f2]=f1;
        bin[f1]=t;
    }

}

int main()
{
    int ans,i,j,k,num,u,v;
    while(~scanf("%d",&n)&&n)
    {
        scanf("%d",&m);
        for(i=0;i<m;i++)
        {
            scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
        }
        for(i=0;i<=n;i++)
            bin[i]=-1;
        sort(e,e+m,cmp);
        for(i=0,ans=0,num=0;i<m;i++)
        {
            u=e[i].u;
            v=e[i].v;
            if(Find(u)!=Find(v))
            {
                num++;
                Union(u,v);
                ans+=e[i].w;
            }
            if(num>=n-1) break;
        }
        printf("%d
",ans);
    }
    return 0;
}