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, return f 阅读全文
摘要：
Given a linked list, swap every two adjacent nodes and return its head. For example, Given 1->2->3->4, you should return the list as 2->1->4->3. Your 阅读全文
摘要：
Given an integer, write a function to determine if it is a power of three. Follow up: Could you do it without using any loop / recursion? 不用递归和循环,这里有一 阅读全文