Цикли в граф

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

class UnionFind{
    vector<int> parents;
public:
    UnionFind(int n) : parents(n){
        for(int i = 0; i < n; i++)
            parents[i] = i;
    }

    int find(int num){
        if(parents[num] == num)
            return num;
        return parents[num] = find(parents[num]);
    }
    bool unite(int a, int b){
        int parentA = find(a);
        int parentB = find(b);

        if(parentA == parentB)
            return false;

        parents[parentA] = parentB;
        return true;
    }
};

int main() {
    int n, m, u, v, w;
    cin >> n >> m;
    UnionFind uf(n);
    vector<pair<int, pair<int, int>>> edges;

    for(int i = 0; i < m; i++){
        cin >> u >> v >> w;
        edges.push_back({w, {v, u}});
    }

    sort(edges.rbegin(), edges.rend());
    long long sum = 0;
    for(auto edge : edges){
        if(!uf.unite(edge.second.first, edge.second.second))
            sum += edge.first;
    }
    cout << sum;
    return 0;
}