SDUT OJ-2896

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cstring>
const int N = 50001;
const int INF = 200001;
using namespace std;
struct node{
    int u,w,v;
}edge[INF];
int father[N],n,m,ans;
int cmp(const void *a,const void *b)
{
    node *X,*Y;
    X = (struct node *)a;
    Y = (struct node *)b;
    return X->w - Y->w ;
}
int find(int r)
{
    int i=r,j;
    while(father[r]!=r)
    {
        r = father[r];
    }
    while(father[i]!=r)
    {
        j = father[i];
        father[i] = r;
        i = j;
    }
    return r;
}

void init()
{
    for(int i = 1; i <= n; i++)
        father[i] = i;
}
void kruskal()
{
    init();
    for(int i = 0; i < m; i++)
    {

        int uu = find(edge[i].u);
        int vv = find(edge[i].v);
        if(uu != vv)
        {
            father[uu] = vv;
            ans += edge[i].w;
        }
    }
     printf("%d\n",ans);
}
int main()
{
        while(~scanf("%d%d",&n,&m))
       {
          ans = 0;
        for(int i =0;i<m;i++)
            scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w);
        
        qsort(edge,m,sizeof(edge[0]),cmp);
        kruskal();
       }

    return 0;
}
 



/**************************************

	Result		: Accepted 
	Take Memory	: 7704K 
	Take Time	: 470MS 
	Submit Time	: 2014-06-21 16:44:10  
**************************************/