快速排序

#include<iostream>
using namespace std;
void quicksort(int *arr, int left, int right)
{
    if(left < right)
    {
        int i = left;
        int j = right;
        int temp = arr[i];
        while(i < j)
        {
            while(i < j && arr[j] > temp)
            {
                j--;
            }
            if(i < j)
            {
                arr[i] = arr[j];//  arr[i++] = arr[j];
                i++;
            }
            while(i < j && arr[i] < temp)
            {
                i++;
            }
            if(i < j)
            {
                arr[j] = arr[i]; // arr[j--] = arr[i];
                j--;
            }
        }
        arr[i] = temp;
        quicksort(arr, left, i-1);
        quicksort(arr, i+1, right);
    }
}

int main()
{
    int arr[] = {30, 20, 40, 20, 10, 40, 60, 50,90,70, 70};
    int count = sizeof(arr)/sizeof(int);
    cout << "Before:" << endl;
    for(int i = 0; i < count; i++)
    {
        cout << arr[i] << " ";
    }
    cout << endl;
    quicksort(arr, 0, count - 1);
    cout << "After:" << endl;
    for(int i = 0; i < count; i++)
    {
        cout << arr[i] << " ";
    }
    cout << endl;
}