Cod sursa(job #3355495)

Utilizator TianaInfoLitcanu Tiana TianaInfo Data 22 mai 2026 22:14:11
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.41 kb
// Kruskal - se sorteaza muchiile, dupa care se unesc subarborii intre care se gaseste muchia de cost minim
#include <bits/stdc++.h>
using namespace std;

struct muchie
{
    int a,b,c;
};
const int nmax=200005,mmax=400005;
muchie muchii[mmax];
int tata[nmax],rangul[nmax],sol_a[nmax],sol_b[nmax],n,m;
ifstream fin("apm.in");
ofstream fout("apm.out");
int radacina(int x)
{
    if(tata[x]==x)return x;
    tata[x]=radacina(tata[x]);
    return tata[x];
}

void unire(int x,int y)
{
    x=radacina(x);
    y=radacina(y);
    if(x==y)return;
    if(rangul[x]<rangul[y])tata[x]=y;
    else if(rangul[y]<rangul[x])tata[y]=x;
    else
    {
        tata[y]=x;
        rangul[x]++;
    }
}

int main()
{

    fin>>n>>m;
    for(int i=1; i<=m; i++)fin>>muchii[i].a>>muchii[i].b>>muchii[i].c;
    sort(muchii+1,muchii+m+1,[](muchie x, muchie y)
    {
        return x.c<y.c;
    });

    for(int i=1; i<=n; i++)
    {
        tata[i]=i;
        rangul[i]=0;
    }
    long long cost=0;
    int nr=0;
    for(int i=1; i<=m&&nr<n-1; i++)
    {
        int x=muchii[i].a,y=muchii[i].b,c=muchii[i].c;
        if(radacina(x)!=radacina(y))
        {
            unire(x,y);
            cost+=c;
            nr++;
            sol_a[nr]=x;
            sol_b[nr]=y;
        }
    }
    fout<<cost<<'\n'<<nr<<'\n';
    for(int i=1; i<=nr; i++)fout<<sol_a[i]<<' '<<sol_b[i]<<'\n';

    return 0;
}