class Solution {

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

List<Integer>[] bucket = new List[nums.length+1];

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

for(int num:nums)

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

for(int key:map.keySet())

{

int freq = map.get(key);

if(bucket[freq] == null)

bucket[freq] = new LinkedList<>();

bucket[freq].add(key);

}

List<Integer> result = new LinkedList<>();

for(int pos = bucket.length-1; pos >= 0 && result.size() < k; pos--)

{

if(bucket[pos] != null)

result.addAll(bucket[pos]);

}

return result;

}

}