폰켓몬→ boxed()★+ collectingAndThen()

나의 풀이 

import java.util.*;
class Solution {
    public int solution(int[] nums) {
        int choice_cnt = nums.length/2;
        Integer[] arr = Arrays.stream(nums).boxed().toArray(Integer[]::new);
        Set<Integer> set = new HashSet<Integer>(Arrays.asList(arr));
        int kind_cnt=set.size();
        if(choice_cnt>kind_cnt){
            return kind_cnt;
        } else{
            return choice_cnt;
        }
    }
}

 

 

다른 사람의 풀이 

import java.util.Arrays;
import java.util.stream.Collectors;

class Solution {
    public int solution(int[] nums) {
        return Arrays.stream(nums)
                .boxed()
                .collect(Collectors.collectingAndThen(Collectors.toSet(),
                        phonekemons -> Integer.min(phonekemons.size(), nums.length / 2)));
    }
}

▶ boxed() ->IntStream 기본형 스트림을 Stream<Integer> 타입으로 바뀌준다.

 

▶ collectingAndThen() 연구 필요