kruskal_own_version

#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;

#define si(n) scanf("%d",&n)
#define f first
#define s second
#define mp(a,b) make_pair(a,b)
#define MAX 10004

vector<int>graph[MAX];
vector<pair<int,pair<int,int> > >edge;
int n,m,parent[MAX],rnk[MAX];

void make_set (int v) {
    parent[v] = v;
    rnk[v] = 0;
}

int find_set (int v) {
    if (v == parent[v])
        return v;
    return parent[v] = find_set (parent[v]);
}

void union_sets (int a, int b) {
    a = find_set (a);
    b = find_set (b);
    if (a != b) {
        if (rnk[a] < rnk[b])
            swap (a, b);
        parent[b] = a;
        if (rnk[a] == rnk[b])
            ++rnk[a];
    }
}

int main()
{
    int i,j;
    si(n);si(m);
    for(i=0;i<m;i++){
        int u,v,w;
        si(u);si(v);si(w);
        graph[u].push_back(v);
        graph[v].push_back(u);
        edge.push_back(mp(w,mp(u,v)));
    }
    sort(edge.begin(),edge.end());
    long long MST=0;

    for(i=1;i<=n;i++)
        make_set(i);

    for(i=0;i<m;i++){
        int u=edge[i].s.f,v=edge[i].s.s,w=edge[i].f;
        if(find_set(u)==find_set(v))
            continue;
        MST+=w;
        union_sets(u,v);
    }

    cout<<MST<<endl;
    return 0;
}