요격 시스템 (연습문제)

원본 : https://school.programmers.co.kr/learn/courses/30/lessons/181188

프로그래머스

 

풀이

import java.util.Arrays;

class Solution {
    public int solution(int[][] targets) {
        Arrays.sort(targets, (o1, o2) -> {
            if (o1[0] != o2[0]) {
                return Integer.compare(o1[0], o2[0]);
            } else {
                return Integer.compare(o2[1], o1[1]);
            }
        });

        int cnt = 1;
        int start = targets[0][0];
        int end = targets[0][1];

        for (int[] target : targets) {
            if (target[1] > start && target[0] < end) {
                start = Math.max(start, target[0]);
                end = Math.min(end, target[1]);
            } else {
                start = target[0];
                end = target[1];
                cnt++;
            }
        }

        return cnt;
    }
}