算法学习笔记之快速排序

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AlgorithmTest
{
    class QuickSort
    {
        private int Partition ( int[] arr, int p, int r )
        {
            int x = arr[r];
            int j = p -1;
            for (int i = p; i < r; i++)
            {
                if (arr[i] <= x)
                {
                    j++;
                    int temp1 = arr[j];
                    arr[j] = arr[i];
                    arr[i] = temp1;
                }
            }
            int temp2 = arr[++j];
            arr[j] = x;
            arr[r] = temp2;
            return j;
        }

        public void Quick_Sort ( int[] arr, int p, int r )
        {
            if (p < r)
            {
                int q = Partition(arr, p, r);
                Quick_Sort(arr, p, q-1);
                Quick_Sort(arr, q + 1, r);
            }
        }
    }
}