Cod sursa(job #2663515)

Utilizator stanciucalinStanciu Calin stanciucalin Data 26 octombrie 2020 17:16:25
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.72 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

ifstream f("apm.in");
ofstream g("apm.out");

class Edge{

public:

    int first;
    int second;

    int price;
};

int n, m;
Edge * lm;

int * t;

vector <Edge> selected;
int price_min;

bool comp(Edge i, Edge j){

    if(i.price < j.price)
        return 1;

    return 0;
}

int get_root(int node){

    if(t[node] > 0){

        int root = get_root(t[node]);
        t[node] = root;

        return root;
    }
    else
        return node;
}

bool check(int i){

    int root_first = get_root(lm[i].first);
    int root_second = get_root(lm[i].second);

    if(root_first == root_second)
        return 0;

    if(t[root_first] <= t[root_second]){

        t[root_first] += t[root_second];
        t[root_second] = root_first;
    }
    else{

        t[root_second] += t[root_first];
        t[root_first] = root_second;
    }

    return 1;
}

void Kruskal(){

    sort(lm, lm + m, comp);

    for(int i = 0; i < m; i++)

        if(check(i)){

            price_min += lm[i].price;
            selected.push_back(lm[i]);
        }
}

int main(){

    f >> n >> m;

    lm = new Edge[m];
    t = new int[n + 1];

    for(int i = 0; i <= n; i++)
        t[i] = -1;

    int x, y, c;
    for(int i = 0; i < m; i++){

        f >> x >> y >> c;

        lm[i].first = x;
        lm[i].second = y;
        lm[i].price = c;
    }

    Kruskal();

    g << price_min << '\n';
    g << selected.size() << '\n';

    for(int i = 0; i < selected.size(); i++)

        g << selected[i].first << " " << selected[i].second << '\n';

    return 0;
}