快速排序法

#include <bits/stdc++.h>
using namespace std;
void quick_sort(int a[],int b,int e)
{
    if(b>=e) return;
    int temp = a[b];
    int i = b,j = e;
    while(i<j)
    {
        while(j>i&&a[j]>=temp) j--;//注意这里一定要找到严格小于的,否则会出错
        while(j>i&&a[i]<=temp) i++;//注意这里一定要找到严格大于的,否则会出错
        if(i<j) swap(a[i],a[j]);
    }
    a[b] = a[i];
    a[i] = temp;
    quick_sort(a,b,i-1);
    quick_sort(a,i+1,e);
}
int main()
{
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int n;
    cin>>n;
    int a[n+1];
    for (int i = 1;i<=n;i++) cin>>a[i];
    quick_sort(a,1,n);
    for (int i = 1;i<=n;i++) cout<<a[i]<<" ";
    return 0;
}