Maximum Spanning tree in C++

#include <bits/stdc++.h>
using namespace std;
int printheap(int N){return 0;}
int set_min_vertex(vector<int> value, vector<bool> set_mst)
{
    int minimum = INT_MAX, vertex,a=value.size();
    for (int i = 0; i < a; i++)
    {
        if (set_mst[i] == false && value[i] < minimum)
        {
            vertex = i;
            minimum = value[i];
        }
    }
    return vertex;
}

int find_mst(vector<vector<int>> graph)
{
    int v=graph.size();
    int parent[v];
    vector<int> value(v, INT_MAX);
    vector<bool> set_mst(v, false);
    parent[0] = -1;
    value[0] = 0;

    for (int i = 0; i < v - 1; i++)
    {
        int u = set_min_vertex(value, set_mst);
        set_mst[u] = true;
        for (int j = 0; j < v; j++)
        {
            if (graph[u][j] != 0 && set_mst[j] == false && graph[u][j] < value[j])
            {
                value[j] = graph[u][j];
                parent[j] = u;
            }
        }
    }
  int sum=0;
    for (int i = 1; i < v; i++)
    {
        sum+= graph[i][parent[i]];
    }
    return sum;
}
int main()
{
   int t,n,m;
   cin>>t;
   while(t--)
   {
       cin>>n>>m;
        vector<vector<int>> vec(n,vector<int>(n));
        while(n--)
        {
            int a,b,c;
            cin>>a>>b>>c;
            vec[a-1][b-1]=vec[b-1][a-1]=-c;
        }
        cout<<-find_mst(vec)<<endl;
   }
	return 0;
}