c#快速排序的递归与非递归形式

递归形式的C＃快速排序算法：

using System;class QuickSort{    public static void Sort(int[] arr, int low, int high)    {        if (low < high)        {            int pivot = Partition(arr, low, high);            Sort(arr, low, pivot - 1);            Sort(arr, pivot + 1, high);        }    }    public static int Partition(int[] arr, int low, int high)    {        int pivot = arr[high];        int i = low - 1;        for (int j = low; j < high; j++)        {            if (arr[j] < pivot)            {                i++;                int temp = arr[i];                arr[i] = arr[j];                arr[j] = temp;            }        }        int temp1 = arr[i + 1];        arr[i + 1] = arr[high];        arr[high] = temp1;        return i + 1;    }    public static void PrintArray(int[] arr)    {        foreach (int num in arr)        {            Console.Write(num + " ");        }        Console.WriteLine();    }    public static void Main()    {        int[] arr = { 12, 11, 13, 5, 6, 7 };        int n = arr.Length;        Console.WriteLine("Original array:");        PrintArray(arr);        Sort(arr, 0, n - 1);        Console.WriteLine("Sorted array:");        PrintArray(arr);    }}

非递归形式的C#快速排序算法：

using System;using System.Collections.Generic;class QuickSort{    public static void Sort(int[] arr, int low, int high)    {        Stack<int> stack = new Stack<int>();        stack.Push(low);        stack.Push(high);        while (stack.Count > 0)        {            high = stack.Pop();            low = stack.Pop();            int pivot = Partition(arr, low, high);            if (pivot - 1 > low)            {                stack.Push(low);                stack.Push(pivot - 1);            }            if (pivot + 1 < high)            {                stack.Push(pivot + 1);                stack.Push(high);            }        }    }    public static int Partition(int[] arr, int low, int high)    {        int pivot = arr[high];        int i = low - 1;        for (int j = low; j < high; j++)        {            if (arr[j] < pivot)            {                i++;                int temp = arr[i];                arr[i] = arr[j];                arr[j] = temp;            }        }        int temp1 = arr[i + 1];        arr[i + 1] = arr[high];        arr[high] = temp1;        return i + 1;    }    public static void PrintArray(int[] arr)    {        foreach (int num in arr)        {            Console.Write(num + " ");        }        Console.WriteLine();    }    public static void Main()    {        int[] arr = { 12, 11, 13, 5, 6, 7 };        int n = arr.Length;        Console.WriteLine("Original array:");        PrintArray(arr);        Sort(arr, 0, n - 1);        Console.WriteLine("Sorted array:");        PrintArray(arr);    }}