[PS][그리디]/[BOJ][1931][회의실 배정]

boj1931.cpp

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

int n;
vector<pair<int, int > > v;

bool compare(pair<int, int> a, pair<int, int> b) {
	if(a.second != b.second) return a.second < b.second;
	else return a.first < b.first;
}

int main(void) { 
	cin >> n;
	pair<int, int> t;
	for (int i = 0; i < n; i++) {
		cin >> t.first >> t.second;
		v.push_back(t);
	}
	sort(v.begin(), v.end(), compare);

	int ans = 1;
	t = v[0];
	for (int i = 1; i < v.size(); i++) {
		if (t.second <= v[i].first) {
			ans++;
			t = v[i];
		}
	}
	cout << ans << "\n";
	return 0;
}