[BOJ] 2750번 : 수 정렬하기

1. problem : 

https://www.acmicpc.net/problem/2750

 

2. solution 1 :

#include <bits/stdc++.h>
using namespace std;
int n;
int arr[1005];

void quick_sort(int st, int en) {
	if (en <= st + 1) return; 
	int lidx = st + 1;
	int ridx = en - 1;  
	int pivot = arr[st];
	while (1) {
		while (lidx <= ridx && pivot >= arr[lidx]) lidx++; 
		while (lidx <= ridx && pivot <= arr[ridx]) ridx--; 
		if (lidx > ridx) break; 
		swap(arr[lidx], arr[ridx]);
	}
	swap(arr[ridx], arr[st]);
	quick_sort(st, ridx);
	quick_sort(ridx + 1, en); 
}
int main(void) {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n; 
	for (int i = 0; i < n; i++) cin >> arr[i]; 
	quick_sort(0, n);
	for (int i = 0; i < n; i++) cout << arr[i] << '\n';
}