BOJ 11651: 좌표 정렬하기2

#BOJ 11651: 좌표 정렬하기2

11651번: 좌표 정렬하기 2

#코드

#include<iostream> // #include<bits/stdc++.h>

using namespace std;

int n;
pair<int, int> arr[100001];
pair<int, int>tmp[100001];
void merge(int st, int en, int k)
{
	int mid = (st + en) / 2;
	int a = st;
	int b = mid;

	for (int i = st; i < en; i++) {
		if (a == mid) {
			tmp[i] = arr[b++];
		}
		else if (b == en) {
			tmp[i] = arr[a++];
		}
		else if (arr[a].first <= arr[b].first && k == 0) tmp[i] = arr[a++];
		else if (arr[a].second <= arr[b].second && k == 1) tmp[i] = arr[a++];
		else tmp[i] = arr[b++];
	}
	for (int i = st; i < en; i++)
		arr[i] = tmp[i];
}
void merge_sort(int st, int en, int k) {
	if (en - st == 1) return;
	int mid = (st + en) / 2;
	
	merge_sort(st, mid, k);
	merge_sort(mid, en, k);
	merge(st, en, k);

}
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	for (int i = 0; i < n; i++)
		cin >> arr[i].first >> arr[i].second;
	merge_sort(0, n, 0); // x 기준 정렬
	merge_sort(0, n, 1); // y기준 정렬

	for (int i = 0; i < n; i++)
		cout << arr[i].first << ' ' << arr[i].second << '\n';
	return 0;
}