https://school.programmers.co.kr/learn/courses/30/lessons/42884

제출 코드

import java.util.Arrays;
class Solution {
    public int solution(int[][] routes) {
        int answer = 1;
        Arrays.sort(routes, (o1, o2) -> o1[1] - o2[1]);
        int cctv = routes[0][1];
        for (int i = 1; i < routes.length; i++){
            if (cctv < routes[i][0]) {
                answer++;
                cctv = routes[i][1];
            }
        }
        return answer;
    }
}