给定一个整数 (32位有符整数型),请写出一个函数来检验它是否是4的幂.示例:当 num = 16 时 ,返回 true . 当 num = 5时,返回 false.问题进阶:你能不使用循环/递归来解决这个问题吗? 详见:https://leetcode.com/problems/power-of-four/description/ C++: 方法一: class Solution { public: bool isPowerOfFour(int num) { while(num&&(nu…

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…

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:…

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. Follow up: Could you solve it without loops/recursion? 答案: 判断一个数是否是4的幂,不能使用循环和递归: 前面我们已经做过一…

Matrix Power Series Time Limit: 3000MS Memory Limit: 131072K Total Submissions: 19338 Accepted: 8161 Description Given a n × n matrix A and a positive integer k, find the sum S = A + A2 + A3 + - + Ak. Input The input contains exactly one test case. T…

传送门 Description 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? 思路 题意:不使用循环和递归,求一个数是否是4的…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 递归 迭代 位运算 函数法 日期 [LeetCode] 题目地址:https://leetcode.com/problems/power-of-four/ Total Accepted: 9305 Total Submissions: 28083 Difficulty: Easy 题目描述 Given an integer (signed 32 bi…

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…

题意:判断一个数是不是4的幂数,和Power of two类似. 先判断num是否大于0,再判断num是否能开根号,最后判断num开根号后的数是否是2^15的约数. 提示:4的幂数开根号就是2的幂数. 注意:判断一个双精度数a是否是0,请用fabs(a)<一个极小的数,如本题中用的是1e-9. class Solution { public: bool isPowerOfFour(int num) { ) && (fabs(( ) && ((<<) % (…