Cod sursa(job #2576555)

Utilizator nTropicManescu Bogdan Constantin nTropic Data 6 martie 2020 20:23:42
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.36 kb
#include <bits/stdc++.h>

using namespace std;

const int len = 400005;
int m, n, parent[len], level[len], cost;
vector<pair<int, int> > sol;

struct edge {
    int x, y, c;
} e[len];

bool cmp(edge a, edge b) {
    return a.c < b.c;
}

void make_set(int k) {
    parent[k] = k;
    level[k] = 1;
}

int find_set(int k) {
    if (parent[k] == k)
        return k;
    return parent[k] = find_set(parent[k]);
}

void union_sets(int x, int y) {
    x = find_set(x);
    y = find_set(y);
    if (x != y) {
        if (level[x] < level[y])
            swap(x, y);
        parent[y] = x;
        if (level[x] == level[y])
            level[x]++;
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    freopen("apm.in", "r", stdin);
    freopen("apm.out", "w", stdout);

    cin >> n >> m;
    for (int i = 0; i < m; i++)
        cin >> e[i].x >> e[i].y >> e[i].c;
    sort(e, e + m, cmp);
    for (int i = 0; i < m; i++)
        make_set(i);

    for (int i = 0; i < m && !sol.empty() < n; i++)
        if (find_set(e[i].x) != find_set(e[i].y)) {
            cost += e[i].c;
            union_sets(e[i].x, e[i].y);
            sol.push_back({e[i].x, e[i].y});
        }

    cout << cost << "\n" << n - 1 << "\n";
    for (auto& it : sol)
        cout << it.first << " " << it.second << "\n";
}