使用随机数选取数，但第五个测试点还是超时了。

#include <iostream>
#include <cstring>
#include <ctime>
#define MAXN 100010
using namespace std;
int a[MAXN];

void swap(int num[], int i, int j) {
    int temp = num[i];
    num[i] = num[j];
    num[j] = temp;
}

void qSort(int a[], int low, int high) { 
    if (low >= high) return;
    
    srand(time(0));
    int i = low, j = high;
    int randPivot = rand() % (high - low + 1) + low;
    int key = a[randPivot];
    swap(a, low, randPivot);
    while (i < j) {
        while (i < j && a[j] >= key) --j;
        while (i < j && a[i] <= key) ++i;
        swap(a, i, j);
    }
    swap(a, i, low);
    qSort(a, i + 1, high);
    qSort(a, low, i - 1);
}

int main() {
    int n;
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        cin >> a[i]; 
    }
    qSort(a, 1, n);
    for(int i = 1; i < n; ++i) {
        cout << a[i] << " ";
    }
    cout << a[n];
    return 0;
}