answer-02.java

package br.com.zbra;

import java.util.*;

public class Main {

    public static void main(String[] args) {
        int[] arr = { 1, 1, 1, 2, 2, 3 };
        System.out.println(Arrays.toString(mostFrequentElements(arr, 2)));
    }

    static int[] mostFrequentElements(int[] arr, int k) {
        int n = arr.length;
        int[] result = new int[k];
        Map<Integer, Integer> map = new HashMap<Integer, Integer>();

        for (int i = 0; i < n; i++) {
            map.put(arr[i], map.getOrDefault(arr[i], 0) + 1);
        }

        List<Map.Entry<Integer, Integer>> list = new ArrayList<Map.Entry<Integer, Integer>>(map.entrySet());

        Collections.sort(list, (e1, e2) -> {
            if (e1.getValue() == e2.getValue()) {
                return e2.getKey() - e1.getKey();
            }
            return e2.getValue() - e1.getValue();
        });

        for (int i = 0; i < k; i++) {
            result[i] = list.get(i).getKey();
        }
        return result;
    }
}