Shuffle in O(N) time, vastly faster than the original version that calls RemoveAt().
static Random r = new Random();
public static IEnumerable<T> Randomize<T>(this IEnumerable<T> source)
{
var list = source.ToList();
for (int i = 0; i < list.Count; i++)
Swap(list, i, r.Next(list.Count));
return list;
}
public static void Swap<T>(List<T> list, int i, int j)
{
T tmp = list[i];
list[i] = list[j];
list[j] = tmp;
}
