private static void Backtrack(MagicSquare ms)
{
if (!ms.IsReady())
{
// candidate values are from 1 to 9 in case of a magic square of size 3
for (int i = 1; i < MagicSquare.Size * MagicSquare.Size + 1; i++)
{
if (!ms.CandidateUsed(i))
{
MagicSquare msCopy = ms.DeepCopy();
msCopy.SetCandidate(i);
Backtrack(msCopy);
}
}
}
}
