public class Solution
extends Object
692 - Top K Frequent Words\.
Medium
Given an array of strings `words` and an integer `k`, return _the_ `k` _most frequent strings_.
Return the answer **sorted** by **the frequency** from highest to lowest. Sort the words with the same frequency by their **lexicographical order**.
**Example 1:**
**Input:** words = ["i","love","leetcode","i","love","coding"], k = 2
**Output:** ["i","love"]
**Explanation:** "i" and "love" are the two most frequent words. Note that "i" comes before "love" due to a lower alphabetical order.
**Example 2:**
**Input:** words = ["the","day","is","sunny","the","the","the","sunny","is","is"], k = 4
**Output:** ["the","is","sunny","day"]
**Explanation:** "the", "is", "sunny" and "day" are the four most frequent words, with the number of occurrence being 4, 3, 2 and 1 respectively.
**Constraints:**
* `1 <= words.length <= 500`
* `1 <= words[i] <= 10`
* `words[i]` consists of lowercase English letters.
* `k` is in the range `[1, The number of **unique** words[i]]`
**Follow-up:** Could you solve it in `O(n log(k))` time and `O(n)` extra space?