폰켓몬

https://school.programmers.co.kr/learn/courses/30/lessons/1845

프로그래머스

import java.util.*;

public class Solution {
    public int solution(int[] num_list) {
        int answer = 0;
        HashMap<Integer, Integer> arr = new HashMap<>();
        for (int i = 0; i < num_list.length; i++) arr.put(num_list[i], arr.getOrDefault(num_list[i],0)+1);
        answer = Math.min(num_list.length/2, arr.size());
        return answer;
    }


    public static void main(String[] args) {
        Solution T = new Solution();
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) arr[i] = in.nextInt();

        System.out.println(T.solution(arr));
    }
}

해시맵으로 풀엇는데 set을 이용하면 애초에 중복이 안들어가니까 set이 더 효율적인거 같다