귤 고르기 (연습문제)

원본 : https://school.programmers.co.kr/learn/courses/30/lessons/138476

프로그래머스

 

풀이

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

class Solution {
    public int solution(int k, int[] tangerine) {
        int answer = 0;
        Map<Integer, Integer> sizeAndCntMap = new HashMap<>();

        for (int size : tangerine) {
            if (sizeAndCntMap.containsKey(size)) {
                sizeAndCntMap.replace(size, sizeAndCntMap.get(size) + 1);
            } else {
                sizeAndCntMap.put(size, 1);
            }
        }

        List<Integer> cntList = sizeAndCntMap.values().parallelStream().sorted((o1, o2) -> o2 - o1).collect(Collectors.toList());
        int cntSum = 0;

        for (int cnt : cntList) {
            answer++;
            cntSum += cnt;

            if (cntSum >= k) {
                break;
            }
        }

        return answer;
    }
}