/// <summary>
/// We perform all permutations of data.
/// </summary>
/// <param name="data">The input data.</param>
/// <returns></returns>
public static List <T[]> Permutate <T>(T[] data)
{
// We find all permutations.
List <T[]> res = new List <T[]>((int)Factorial.Eval((uint)data.Length));
Permutate(data.Clone() as T[], 0, res);
return(res);
}