poj 1861 Network

#include <iostream>            //kruskal
using namespace std;
const int max_ve=1005,max_ed=15005;
int n,m,i,flag[max_ed];        //n,m分别记录顶点数和边数
struct node
{
    int par;
}vertex[max_ve];
struct Edge 
{
    int u,v,weigh;
}edge[max_ed];
int cmp(const void* a,const void* b)
{
    return (*(Edge*)a).weigh-(*(Edge*)b).weigh;
}
int find_p(int j)
{
    if(vertex[j].par!=j)
    {
        vertex[j].par=find_p(vertex[j].par);
    }
    return vertex[j].par;
}
bool union_set(int s,int t)
{
    int os=find_p(s),ot=find_p(t);
    if(os==ot)
        return false;
    vertex[ot].par=os;
    return true;
}
int main()
{
    /*freopen("F:\\in.txt","r",stdin);*/
    int ct,ms;
    scanf("%d%d",&n,&m);        
    for(i=1;i<=n;++i)    //顶点从1到n
    {
        vertex[i].par=i;
    }
    for(i=0;i<m;++i)
    {
        scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].weigh);
    }
    qsort(edge,m,sizeof(edge[0]),cmp);
    ms=0;ct=0;
    for(i=0;i<m&&ct<n-1;++i)    //当ct==n-1说明有n-1条边，即所有的顶点都已连接上，终止算法
    {
        if(union_set(edge[i].u,edge[i].v))
        {
            ++ct;    //边数+1
            ms=max(ms,edge[i].weigh);
            flag[i]=1;
        }
    }
    printf("%d\n%d\n",ms,ct);
    for(i=0;i<m;++i)
        if(flag[i])
            printf("%d %d\n",edge[i].u,edge[i].v);
    return 0;
}