kruskal

#include <bits/stdc++.h>

using namespace std;
ifstream fin("kruskal.in");
ofstream fout("kruskal.out");
struct muchie
{
    int x,y,c;
};
muchie a[1001];
struct afis
{
    int x,y;
};
afis v[1001];
int t[1001],n,m;
void Union(int x,int y)
{
    t[y]=x;
}
int Find(int x)
{
    int rad,y;
    rad=x;
    while(t[rad]!=0) rad=t[rad];
    while(x!=rad)
    {
        y=t[x];
        t[x]=rad;
        x=y;
    }
    return rad;
}
void Citire()
{
    int i;
    fin>>n>>m;
    for(i=1;i<=m;i++) fin>>a[i].x>>a[i].y>>a[i].c;
}
bool Cmp(muchie A, muchie B)
{
    return A.c<B.c;
}
void Kruskal()
{
    int p,q,costmin,cnt=1;
    sort(a+1,a+m+1,Cmp);
    costmin=0;
    for(int i=1;i<=m;i++)
    {
        p=Find(a[i].x);
        q=Find(a[i].y);
        if(p!=q)
        {
            v[cnt].x=a[i].x;
            v[cnt].y=a[i].y;
            cnt++;
            costmin+=a[i].c;
            Union(p,q);
        }
    }
    fout<<costmin<<"\n";
    for(int i=1;i<cnt;i++) fout<<v[i].x<<" "<<v[i].y<<"\n";
}
int main()
{
    Citire();
    Kruskal();
    return 0;
}