Cod sursa(job #2678051)

Utilizator robeert.77Chirica Robert robeert.77 Data 28 noiembrie 2020 00:26:49
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.41 kb
#include <bits/stdc++.h>
#define ll long long
using namespace std;
ifstream fin ("apm.in");
ofstream fout ("apm.out");

const int MAXN = 2e5 + 5, MAXM = 4e5 + 5;
int n, m, tree[MAXN];
struct edge {
    int node1, node2, cost;
};

bool compareByCost(edge i, edge j) {
    return (i.cost < j.cost);
}

int findRoot(int node) {
    if (node == tree[node])
        return node;
    tree[node] = findRoot(tree[node]);
    return tree[node];
}

int main() {
    fin.tie(0);
    fout.tie(0);
    ios::sync_with_stdio(0);
    fin >> n >> m;
    vector<edge> graph(m);
    for (int i = 0; i < m; i++)
        fin >> graph[i].node1 >> graph[i].node2 >> graph[i].cost;
    sort(graph.begin(), graph.end(), compareByCost);
    for (int i = 1; i <= n; i++)
        tree[i] = i;

    ll totalCost = 0;
    vector<pair<int, int> > minTree;
    for (int i = 0; i < m; i++) {
        int rootA = findRoot(graph[i].node1);
        int rootB = findRoot(graph[i].node2);
        if (rootA != rootB) {
            minTree.push_back(make_pair(graph[i].node1, graph[i].node2));
            totalCost += graph[i].cost;
            tree[min(rootA, rootB)] = tree[max(rootA, rootB)];
            //tree[rootA] = tree[rootB];
        }
    }

    fout << totalCost << "\n" << n - 1 << "\n";
    for (int i = 0; i < n - 1; i++)
        fout << minTree[i].first << " " << minTree[i].second << "\n";
    return 0;
}