Cod sursa(job #2042965)

Utilizator andreistanStan Andrei andreistan Data 19 octombrie 2017 15:33:46
Problema Arbore partial de cost minim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.17 kb
#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream f("apm.in");
ofstream g("apm.out");
const int INF = 1 << 25;

struct muchie
{
    int i, j, c;
};

int n, m, cost;
muchie M[400001];
int CC[200001], NrM[200000];

void citire()
{
    f >> n >> m;
    for(int i = 1; i <= m; i++)
        f >> M[i].i >> M[i].j >> M[i].c;
}

void afis()
{
    g << cost << '\n' << n - 1 << '\n';
    for(int i = 1; i < n; i++)
        g << M[NrM[i]].i << ' ' << M[NrM[i]].j << '\n';
}

bool comp(const muchie &a, const muchie &b)
{
    return a.c < b.c;
}

int grupa(int i)
{
    if(CC[i] == i)
        return i;
    CC[i] = grupa(CC[i]);
    return CC[i];
}

void Kruskal()
{
    sort(M + 1, M + m + 1, comp);
    for(int i = 1; i <= n; i++)
        CC[i] = i;
    int nm = 0;
    for(int i = 1; i <= m; i++)
    {
        if(grupa(M[i].i) != grupa(M[i].j))
        {
            cost += M[i].c;
            CC[grupa(M[i].i)] = grupa(M[i].j); //reuniunea
            NrM[++nm] = i;
        }
        //if(nm == n - 1) break;
    }
}

int main()
{
    citire();
    Kruskal();
    afis();
    return 0;
}