class Solution {

    public List<Integer> topKFrequent(int[] nums, int k) {

        Map<Integer, Integer> map = new HashMap<>();

        for (Integer num: nums) {

          map.put(num, map.getOrDefault(num, 0) + 1);

        }

        // keep a top frequency heap

        PriorityQueue<Map.Entry<Integer, Integer>> pq = new PriorityQueue<>((a, b) ->

          a.getValue() == b.getValue() ? b.getKey().compareTo(a.getKey()): a.getValue() - b.getValue()

        );

        for (Map.Entry<Integer, Integer> entry: map.entrySet()) {

            pq.offer(entry);

            if (pq.size() > k) {

                pq.poll();

            }

        }

        List<Integer> res = new ArrayList<>();

        // while (!pq.isEmpty()) {

        //     res.add(0, pq.poll().getKey());

        // }

        while (!pq.isEmpty()) {

            res.add(pq.poll().getKey());

        }

        return res;

    }

}

public class Solution {

  public String[] topKFrequent(String[] combo, int k) {

    // Write your solution here.

    Map<String, Integer> map = new HashMap<>();

    for (String s: combo) {

      map.put(s, map.getOrDefault(s, 0) + 1);

    }

    PriorityQueue<Map.Entry<String, Integer>> pq = new PriorityQueue<>(k, new Comparator<Map.Entry<String, Integer>>() {

        @Override

        public int compare(Map.Entry<String, Integer> a, Map.Entry<String, Integer> b) {

          return a.getValue().compareTo(b.getValue());

        }

    });

    for (Map.Entry<String, Integer> mymap: map.entrySet()) {

      pq.offer(mymap);

      if (pq.size() > k) {

        pq.poll();

      }

    }

    String[] res = new String[pq.size()];

    for (int i = res.length - 1; i >= 0; i--) {

      res[i] = pq.poll().getKey();

    }

    return res;

  }

}