Cod sursa(job #2675386)

Utilizator maraboneaMara Bonea marabonea Data 21 noiembrie 2020 15:58:53
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.27 kb
/**
infoarena.ro/problema/apm
Arbore partial de cost minim
*/
#include <algorithm>
#include <fstream>
#define nmax 400005
using namespace std;
ifstream fin("apm.in");
ofstream fout("apm.out");

int vt[nmax],r[nmax],ind[nmax];
int n,m,s,k;
struct muchie
{
    int x,y,c;
}e[nmax];
bool compara(muchie a, muchie b)
{
    return (a.c<b.c);
}
void citire()
{
    fin>>n>>m;
    for(int i=1; i<=m; i++)
    {
        fin>>e[i].x>>e[i].y>>e[i].c;
    }
    sort(e+1,e+m+1,compara);
}
int radacina(int x)
{
    while(vt[x]!=x)
        x=vt[x];
    return x;
}

void unire(int x, int y)
{
    if(r[x]<r[y])
        vt[x]=y;
    if(r[x]>r[y])
        vt[y]=x;
    if(r[x]==r[y])
    {
        vt[y]=x;
        r[x]++;
    }
}
void kruskal()
{
    for(int i=1;i<=n;i++)
        vt[i]=i;
    for(int i=1;i<=m;i++)
    {
        int a=radacina(e[i].x);
        int b=radacina(e[i].y);
        if(a!=b)
        {
            unire(a,b);
            s=s+e[i].c;
            k++;
            ind[k]=i;
        }
    }
}
void afisare()
{
    fout<<s<<endl<<n-1<<endl;
    for(int i=1;i<=k;i++)
    {
        fout<<e[ind[i]].x<<" "<<e[ind[i]].y<<endl;
    }
}
int main()
{
    citire();
    kruskal();
    afisare();
    return 0;
}