/// <summary>
/// Executes a quicksort algorithm given the value and swap methods.
/// </summary>
public static void Sort(Func <long, long> value, Action <long, long> swap, long left, long right)
{
if (left < right)
{
var stack = new System.Collections.Generic.Stack <Pair>();
stack.Push(new Pair(left, right));
while (stack.Count > 0)
{
var pair = stack.Pop();
var pivot = QuickSort.Partition(value, swap, pair.Left, pair.Right);
if (pair.Left < pivot)
{
stack.Push(new Pair(pair.Left, pivot - 1));
}
if (pivot < pair.Right)
{
stack.Push(new Pair(pivot + 1, pair.Right));
}
}
}
}
/// <summary>
/// Partitions everything between left and right in three partitions, smaller than, equal to and larger than pivot.
/// </summary>
/// <remarks>Reference : https://en.wikipedia.org/wiki/Dutch_national_flag_problem </remarks>
public static void ThreewayPartition(Func <long, long> value, Action <long, long> swap, long left, long right,
out long highestLowest, out long lowestHighest)
{
QuickSort.ThreewayPartition(value, swap, left, right, left, out highestLowest, out lowestHighest); // default, the left a pivot.
}