Revise paste Untitled

#include <iostream>
#include <vector>
#include <set>
#include <cstring>
#include <queue>
#include <algorithm>
using namespace std;
const int maxn =305;
int idx[maxn], sz[maxn];
int num_of_union;
void reset_val() {
    for(int i = 0; i < maxn; i++) {
        sz[i] = 1;
        idx[i] = i;
    }
    num_of_union = 0;
}
int find_root(int x) {
    while(idx[x] != x) {
        idx[x] = idx[idx[x]];
        x = idx[x];
    }
    return x;
}
bool is_in_the_same_union(int a, int b) {
    if(find_root(a) == find_root(b)) {
        return true;
    }
    return false;
}
void union_two_elems(int a, int b) {
    int root_a = find_root(a);
    int root_b = find_root(b);
    if(root_a != root_b) {
        num_of_union++;
        if(sz[root_a] < sz[root_b]) {
            sz[root_b] += sz[root_a];
            idx[root_a] = idx[root_b];
        }
        else {
            sz[root_a] += sz[root_b];
            idx[root_b] = idx[root_a];
        }
    }
}
int main() {
   
    int n, m;
    cin >> n >> m;
    
    vector<pair<int, pair<int, int> > > graph;
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        graph.push_back(make_pair(c, make_pair(a, b)));
    }
    sort(graph.begin(), graph.end());
    int MST = 0;
    reset_val();

vector<pair<int, int> > v;
    for(int i = 0; i < m; i++) {
        int c = graph[i].first;
        int a = graph[i].second.first;
        int b = graph[i].second.second;
        
        if(!is_in_the_same_union(a, b)) {
            union_two_elems(a, b);
            v.push_back(make_pair(a, b));
            MST += c;
        }
    }
    int M2 = 2e9;
    for(int i = 0; i < v.size(); i++) {
        int a1 = v[i].first, b1 = v[i].second;
        int mst2 = 0;
        reset_val();
        for(int j =0 ; j < m; j++) {
            if(graph[j].second.first == a1 and graph[j].second.second == b1) continue;
            int c = graph[j].first;
            int a = graph[j].second.first;
            int b = graph[j].second.second;
            if(!is_in_the_same_union(a, b)) {
                union_two_elems(a, b);
                mst2 += c;
            }
        }
        if(num_of_union == n - 1) {
            M2 = min(M2, mst2);
        }
    }
    cout << MST << endl << M2 << endl;
    return 0;
}