TOP K frequent-elements

class Solution {
    public List<Integer> topKFrequent(int[] nums, int k) {
        List<Integer> list = new LinkedList<>();
        Queue<Map.Entry<Integer, Integer>> queue = new PriorityQueue<>(k, new Comparator<Map.Entry<Integer, Integer>>() {
            @Override
            public int compare(Map.Entry<Integer,Integer> e1, Map.Entry<Integer,Integer> e2) {
                
                return e1.getValue() - e2.getValue();
            }
        });
        Map<Integer, Integer> map = new HashMap<>();
        for (int n: nums) {
            map.put(n, map.containsKey(n) ? map.get(n) + 1 : 1);
        }
        for (Map.Entry<Integer, Integer> e: map.entrySet()) {
            if (queue.size() < k) {
                queue.add(e);
            } else if (e.getValue() > queue.peek().getValue()){
                queue.poll();
                queue.add(e);
            }
        }
        while (queue.size() > 0) {
            list.add(queue.poll().getKey());
        }
    
        return list;
    }
}

 

class Solution {
    public List<Integer> topKFrequent(int[] nums, int k) {
        List<Integer> list = new LinkedList<>();
        int count = 0;
        Map<Integer, Integer> map = new HashMap<>();
        Map<Integer, Set<Integer>> table = new HashMap<>();
        for (int n: nums) {
            map.put(n, map.containsKey(n) ? map.get(n) + 1 : 1);
        }
        for (Map.Entry<Integer, Integer> e : map.entrySet()) {
            int val = e.getValue();
            int key = e.getKey();
            if (table.containsKey(val)) {
                Set<Integer> set = table.get(val);
                set.add(key);
                table.put(val, set);
            } else {
                Set<Integer> set = new HashSet<>();
                set.add(key);
                table.put(val, set);
            }
            if (val >= count) count = val;
        }
        while  (list.size() < k) {
            if (table.containsKey(count)) {
                Set<Integer> set = table.get(count);
                for (int n : set) {
                    if (list.size() < k) {
                        list.add(n);
                    } else return list;
                }
            } 
            count--;
            
        }
        
    
        return list;
    }
}