kruskal fallado

#include <iostream>
#include <vector>
#include <math.h>
#include <algorithm>

using namespace std;

struct arista
{
    int desde, hacia, c;
    arista(int _desde, int _hacia, int _c)
    {
        desde = _desde;
        hacia = _hacia;
        c = _c;
    }
};

struct infoA
{
    int x, y;
    infoA(int _x, int _y)
    {
        x = _x;
        y = _y;
    }
};

bool m(const arista &a, const arista &b)
{
    return (a.c < b.c);
}
struct grafo
{
    vector <infoA> ifarol;
    vector <int> idcomp;
    vector < vector <int> > comp;
    vector <arista> aristas;
    vector < vector <int> > grafoF;
    int n, cable = 0;

    void entrada()
    {
        cin >> n;
        idcomp.resize(n+1);
        comp.resize(n+1);
        aristas.resize(n+1);
        grafoF.resize(n+1);
        for(int i = 0; i < idcomp.size(); i++)
            idcomp[i] = i;

        ifarol.push_back(infoA(0,0));
        int f, x, y;
        for(int i = 0; i < n; i++)
        {
            cin >> f, x, y;
            ifarol.push_back(infoA(x,y));
        }

        for(int i = 0; i <= n; i++)
        {
            int x1 = ifarol[i].x;
            int y1 = ifarol[i].y;
            for(int j = 0; j<= n;j++)
            {
                int x2 = ifarol[j].x;
                int y2 = ifarol[j].y;
                int c = sqrt(pow(y1-y2,2)+pow(x1-x2,2)) + 2;

                if(i != j)
                    aristas.push_back(arista(i,j,c));
            }
        }
    }

    void kruskal()
    {
        sort(aristas.begin(),aristas.end(),m);
        for(int i = 0;i < aristas.size(); i++)
        {
            if(esArbol(aristas[i]))
            {
                add(aristas[i]);
                save(aristas[i]);
            }
        }

        cout << cable << endl;
        for(int i = 1; i < grafoF.size(); i++)
        {
            cout << i << " ";
            for(int j = 0; j < grafoF[i].size(); j++)
            {
                cout << grafoF[i][j] << " ";
            }
            cout << endl;
        }
    }

    bool esArbol(arista a)
    {
        int n1 = a.desde;
        int n2 = a.hacia;

        int c1 = idcomp[n1];
        int c2 = idcomp[n2];

        return (c1 != c2);
    }

    void add(arista a)
    {
        int n1 = a.desde, n2 = a.hacia;
        int c1 = idcomp[n1], c2 = idcomp[n2];
        int t1 = comp[c1].size();
        int t2 = comp[c2].size();

        if(t1 > t2)
        {
            swap(n1,n2);
            swap(c1,c2);
            swap(t1,t2);
        }

        for(int i = 0; i < t1; i++)
        {
            int n = comp[c1][i];
            idcomp[n] = c2;
            comp[c2].push_back(n);
        }
    }

    void save (arista a)
    {
        cable += a.c;
        grafoF[a.desde].push_back(a.hacia);
        grafoF[a.hacia].push_back(a.desde);
    }
};
int main()
{
    grafo g;
    g.entrada();
    g.kruskal();
    return 0;
}