Tietoverkko

input/code.cpp:27:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^

#include <iostream>
#include <vector>
#include <algorithm>
#define int long long

using namespace std;

int edustaja[200001];
int koko[200001];

int id(int x){
    while(edustaja[x] != x){
        x = edustaja[x];
    }
    return x;
}

void liita(int a, int b){
    a = id(a);
    b = id(b);
    if(koko[b] > koko[a])swap(a, b);
    koko[a] += koko[b];
    edustaja[b] = a;
}


main(){

    for(int i = 1; i <= 200000; ++i){
    edustaja[i] = i;
    koko[i] = 1;
}
    int n; cin >> n;
    vector<pair<int, pair<int, int>>> edge_list;
    for(int i = 1; i < n; ++i){
        int a, b, x;
        cin >> a >> b >> x;
        edge_list.push_back(make_pair(x, make_pair(a, b)));
    }
    sort(edge_list.rbegin(), edge_list.rend());
    int ans = 0;
    for(auto edge : edge_list){
        int a = edge.second.first;
        int b = edge.second.second;
        int a_size = koko[id(a)];
        int b_size = koko[id(b)];
        ans = ans + a_size * b_size * edge.first;
        liita(a, b);
    }

    cout << ans;

    return 0;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED