## 题目描述：

LeetCode 347. Top K Frequent Elements

Given a non-empty array of integers, return the k most frequent elements.

For example,
Given `[1,1,1,2,2,3]` and k = 2, return `[1,2]`.

Note:

• You may assume k is ...

## 题目描述：

LeetCode 345. Reverse Vowels of a String

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1:

Given s = "hello", return "holle".

Example 2:

Given s = "leetcode", return "leotcede".

## 题目描述：

LeetCode 344. Reverse String

Write a function that takes a string as input and returns the string reversed.

Example:

Given s = "hello", return "olleh".

## Python代码：

``````class Solution(object):
def reverseString ...``````

## 题目描述：

LeetCode 343. Integer Break

Given a positive integer n, break it into the sum of at least two positive integers and maximize the product of those integers. Return the maximum product you can get.

For example, given n = 2, return ...

## 题目描述：

LeetCode 342. Power of Four

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example:
Given num = 16, return true. Given num = 5, return false.

Follow up: Could you solve ...