[LeetCode] 347. Top K Frequent Elements

public class Solution {
    public List<Integer> topKFrequent(int[] nums, int k) {
        Map<Integer,Integer> hash=new HashMap<>();
         List<Integer> list=new ArrayList<Integer>();
            for(int i=0;i<nums.length;i++){
            //可以使用hash.put(nums[i], hash.containsKey(nums[i])? hash.get(nums[i]) + 1 : 1);语句代替
                if(hash.containsKey(nums[i]))
                    hash.put(nums[i], hash.get(nums[i])+1);
                else hash.put(nums[i],1);
            }
            Comparator<Map.Entry<Integer, Integer>> byMapValues = new Comparator<Map.Entry<Integer, Integer>>() {
                @Override
                public int compare(Map.Entry<Integer, Integer> left, Map.Entry<Integer, Integer> right) {
                       return right.getValue().compareTo(left.getValue());//按照单词频率逆序排列
                }
            };
            List<Map.Entry<Integer, Integer>> sortedListMap = new ArrayList<Map.Entry<Integer, Integer>>(hash.entrySet());
            Collections.sort(sortedListMap, byMapValues);
            for(int i=0;i<k;i++)
                list.add(sortedListMap.get(i).getKey());
            return list;
    }
}