快排写法

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int partition(int arr[],int left,int right)
{
    int pivot=arr[right];
    while(left!=right)
    {
        while(left<right&&arr[left]<pivot)left++;
        if(left<right)swap(arr[left],arr[right--]);
        while(left<right&&arr[right]>pivot)right--;
        if(left<right)swap(arr[left++],arr[right]);
    }
    return left;
}
void qsort(int arr[],int left,int right)
{
    if(left>=right)return;
    int index=partition(arr,left,right);
    qsort(arr,left,index-1);
    qsort(arr,index+1,right);
}
int a[10005];
int n;
int main()
{
    cin>>n;
    for(int i=0;i<n;i++)cin>>a[i];
    qsort(a,0,n-1);
    for(int i=0;i<n;i++)cout<<a[i]<<" ";
    cout<<endl;
    return 0;
}