1.quick_sort.cpp

#include<iostream>
#include<algorithm>
using namespace std;
const int N = 100010;
int q[N];

void quick_sort(int q[], int l, int r){
	if(l >= r)	return;
	int i = l - 1, j = r + 1, x = q[l + r >> 1];
	while(i < j){
		do i++;	while(q[i] < x);
		do j--;	while(q[j] > x);
		if(i < j)	swap(q[i], q[j]);
	}
	quick_sort(q, l, j), quick_sort(q, j + 1, r);
}
int main()
{
	int n;	cin >> n;
	for(int i = 0; i < n; i++)	cin >> q[i];
	quick_sort(q, 0, n - 1);
	for(int i = 0; i < n; i++)	cout << q[i] << " ";
	return 0;
}