算法导论 快速排序

#include<iostream>
#include<algorithm>
using namespace std;
int partition(int* &a,int p,int r)
{
    int x=a[r];
    int i=p-1;
    for(int j=p;p<=r-1;p++)
    {
        if(a[j]<=x)
        {
            i=i+1;
            swap(a[i],a[j]);
        }
    }
    swap(a[i+1],a[r]);
    return i+1;
}
void quicksort(int* &a,int p,int r)
{
    if(p<r)
    {
        int q= partition(a,p,r);
        quicksort(a,p,q-1);
        quicksort(a,q+1,r);
    }
}

int main()
{
    const int LEN = 20;
    int b[LEN] = {12, 43, 0, -4, 98, 75, 64, 88, 5, 32, 11, 12, 13, 84, 34, 27, -5, -244, 49, 345};
    int* a = new int[LEN];
    for(int i = 0; i < LEN; i++)
        a[i] = b[i];
    quicksort(a, 0, LEN - 1);
    for(int i = 0; i < LEN; i++)
        cout<<a[i]<<endl;
    return 0;
}