Starting with a positive integer N, we reorder the digits in any order (including the original order) such that the leading digit is not zero. Return true if and only if we can do this in a way such that the resulting number is a power of 2. Example…
leetcode 326. Power of Three(不用循环或递归) 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? 题意是判断一个数是否是3的幂,最简单的也最容易想到的办法就是递归判断,或者循环除. 有另一种方法就是,求log以3为底n的对数.类似 如果n=9,则…
Given an integer, write a function to determine if it is a power of two. Example 1: Input: 1 Output: true Example 2: Input: 16 Output: true Example 3: Input: 218 Output: false 给一个整数,写一个函数来判断它是否为2的次方数. 利用计算机用的是二进制的特点,用位操作,此题变得很简单. 2的n次方的特点是:二进制表示中最高位是…
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…
Starting with a positive integer N, we reorder the digits in any order (including the original order) such that the leading digit is not zero. Return true if and only if we can do this in a way such that the resulting number is a power of 2. Example…
Starting with a positive integer N, we reorder the digits in any order (including the original order) such that the leading digit is not zero. Return true if and only if we can do this in a way such that the resulting number is a power of 2. Example…
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 字典统计每位数字出现的次数 日期 题目地址:https://leetcode.com/problems/reordered-power-of-2/description/ 题目描述 Starting with a positive integer N, we reorder the digits in any order (including the…
function reorderedPowerOf2(N) { var a1 = N.toString().split('') a1.sort((a, b) => a.localeCompare(b) ) var s1 = a1.join('') for (let i = 0; i < 31; i++) { var a2 = String(1 << i).split('') a2.sort((a, b) => a.localeCompare(b) ) if (s1 === a…
Given an integer, write a function to determine if it is a power of two. 分析:这道题让我们判断一个数是否为2的次方数(而且要求时间和空间复杂度都为常数),那么对于这种玩数字的题,我们应该首先考虑位操作 Bit Manipulation.在LeetCode中,位操作的题有很多,比如比如Repeated DNA Sequences 求重复的DNA序列, Single Number 单独的数字, Single Number…
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…
