快速排序

#include<stdio.h>
#include<stdlib.h>
#include<iostream>
#include<algorithm>
#define N 1000000

using namespace std;

int a[N];

void quicksort(int x[], int left, int right)
{
    if(left >= right)return;
    int i = left;
    int j = right;
    swap(x[i], x[(rand() % (right - left + 1)) + left]);
    int key = x[i];
    while(i < j){
        while(i < j && x[j] >= key)j--;
        if(i < j)swap(x[i++], x[j]);
        while(i < j && x[i] <= key)i++;
        if(i < j)swap(x[i], x[j--]);
    }
    quicksort(x, left, i - 1);
    quicksort(x, i + 1, right);
}

int main()
{
    int n;
    while(~scanf("%d", &n)){
        for(int i = 0; i < n; i++){
            cin >> a[i];
        }
        quicksort(a, 0, n - 1);
        for(int i = 0; i < n; i++){
            cout << a[i] << ‘ ‘;
        }
        cout << endl;
    }
    return 0;
}