딩코딩 : Computer Science 블로그

https://www.acmicpc.net/problem/11000

#include <bits/stdc++.h>
using namespace std;

int n;
vector<pair<int, int> > v;
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n;
	for (int i = 0; i < n; i++) {
		int a, b;
		cin >> a >> b;

		v.push_back({ a,b });
	}

	sort(v.begin(), v.end());

	priority_queue<int> Q;

	for (int i = 0; i < n; i++) {
		if (i == 0) {
			Q.push(-v[i].second);
			continue;
		}

		if (v[i].first >= -Q.top()) {
			Q.pop();
			Q.push(-v[i].second);
		}
		else {
			Q.push(-v[i].second);
		}
	}

	cout << Q.size() << '\n';


	return 0;
}