/// <summary>
/// Performs a high-quality random shuffling of the list.
/// Uses a user-provided random number generator, which
/// </summary>
/// <typeparam name="T">The type of elements in the list.</typeparam>
/// <typeparam name="N">The type of numbers generated by the random numbers generator.</typeparam>
/// <param name="list">The calling list object.</param>
/// <param name="generator">A floating-point random number generator for the <typeparamref name="N"/> type.</param>
/// <param name="numericComparer">An optional numeric comparer for <typeparamref name="N"/> type. If <c>null</c>, a standard comparer will be used (if exists, otherwise, an exception will be thrown).</param>
public static void Shuffle <T, N>(this IList <T> list, IRandomFloatingPoint <N> generator, IComparer <N> numericComparer = null)
{
Contract.Requires <ArgumentNullException>(list != null, "list");
Contract.Requires <ArgumentNullException>(generator != null, "generator");
if (numericComparer == null)
{
numericComparer = Comparer <N> .Default;
}
// Генерируем массив пар со случайными ключами,
// сортируем их по ключу (а значения оказываются случайно перемешанными).
List <KeyValuePair <N, T> > pairList = new List <KeyValuePair <N, T> >(list.Count);
foreach (T element in list)
{
pairList.Add(new KeyValuePair <N, T>(generator.Next_SingleInterval(), element));
}
IComparer <KeyValuePair <N, T> > pairComparer = numericComparer.createKVPComparerOnKey <N, T>();
pairList.Sort(pairComparer);
// Восстанавливаем.
for (int i = 0; i < pairList.Count; i++)
{
list[i] = pairList[i].Value;
}
}
