摘要： Given a positive integer num, write a function which returns True if num is a perfect square else False.Note: Do not use any built-in library... 阅读全文

摘要： 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:... 阅读全文

摘要： 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, ... 阅读全文