231. Power of Two Given an integer, write a function to determine if it is a power of two. class Solution { public: bool isPowerOfTwo(int n) { ? (n & (n-)) == : false; } }; 342. Power of Four Given an integer (signed 32 bits), write a function to che…

这三道题目都是一个意思,就是判断一个数是否为2/3/4的幂,这几道题里面有通用的方法,也有各自的方法,我会分别讨论讨论. 原题地址:231 Power of Two:https://leetcode.com/problems/power-of-two/description/ 326 Power of Three:https://leetcode.com/problems/power-of-three/description/ 342 Power of Four :https://leetcod…

这两题我放在一起说是因为思路一模一样,没什么值得研究的.思路都是用对数去判断. /** * @param {number} n * @return {boolean} */ var isPowerOfThree = function(n) { return (Math.log10(n) / Math.log10(3)) % 1 === 0; }; /** * @param {number} num * @return {boolean} */ var isPowerOfFour = functi…

342. Power of Four     Total Accepted: 707 Total Submissions: 2005 Difficulty: Easy 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:…

位运算相关 三道题 231. Power of Two Given an integer, write a function to determine if it is a power of two. (Easy) 分析: 数字相关题有的可以考虑用位运算,例如&可以作为筛选器. 比如n & (n - 1) 可以将n的最低位1删除,所以判断n是否为2的幂,即判断(n & (n - 1) == 0) 代码: class Solution { public: bool isPowerOf…

What is Q&A? Sometimes the fastest way to get an answer from your data is to ask a question using natural language. For example, "what were total sales last year." Use Q&A to explore your data using intuitive, natural language capabiliti…

POJ 1459 Power Network / HIT 1228 Power Network / UVAlive 2760 Power Network / ZOJ 1734 Power Network / FZU 1161 (网络流,最大流) Description A power network consists of nodes (power stations, consumers and dispatchers) connected by power transport lines. A…

一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 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. F…

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 it without loops/recursion? Credits:Special thanks to @yukuairoyfor…

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 it without loops/recursion? 先说明用循环: 如下 class Solution { public: bool…