public int MakeConnected(int n, int[][] connections)
{
if (connections.Length < n - 1)
{
return(-1);
}
QuickUnionUF uf = new QuickUnionUF(n);
int p;
int q;
for (int i = 0; i < connections.Length; i++)
{
p = connections[i][0];
q = connections[i][1];
if (uf.Find(p) != uf.Find(q))
{
uf.Uunion(p, q);
}
}
int requiredEdges = uf.Count - 1;
return(requiredEdges);
}