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:…

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(( ) && ((<<) % (…

题目描述: 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. 解题思路: 位操作. 首先判断是不是只有一位数字为1,其余为0 然后判断为1的位置是不是奇数位 代码如下: class Solution(object): def isPower…

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…

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? 题目标签:Bit Manipulation 这道题目让我们判断一个数字是不是4的…

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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…