326. Power of Three Question Total Accepted: 1159 Total Submissions: 3275 Difficulty: Easy 推断给定整数是否是3的某次方. 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? 完毕此题.…

#-*- coding: UTF-8 -*- class Solution(object):    def isPowerOfThree(self, n):        if n<=0:            return False        while True:            if n==3 or n==1:                return True            tuple=divmod(n,3)            if tuple[1]!=0:  …

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…

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…

326. Power of Three 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? 思路:看这个数取以3为底的对数结果是否为整数,C++中只有自然对数函数log()和以10为底的对数函数log10(),所以要借助换底公式.此处用自然对数会有精度问题,用以10为底的对数…

A. Easy Math Time Limit: 2000ms Memory Limit: 65536KB Given n integers a1,a2,-,an, check if the sum of their square root a1−−√+a2−−√+⋯+an−−√ is a integer. Input The input consists of multiple tests. For each test: The first line contains 1 integer n…

4436: Easy Math Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.scu.edu.cn/soj/problem.action?id=4436 Description Given n integers a1,a2,…,an, check if the sum of their square root a1+a2+…+an is a integer. Input The input consists of multiple…

题目链接:Easy Math 题目大意:给定\(n(1\leqslant n\leqslant 10^{12}),m(1\leqslant m\leqslant 2*10^{9})\),求\(\sum_{i=1}^{m}\mu (i\cdot n)\). 题解:废话少说,直接上公式 $$\mu(i\cdot n)=\left\{\begin{matrix}\mu(i)\cdot\mu(n) & gcd(i,n)==1\\ 0 & other\end{matrix}\right.$$ 设 $…

LeetCode 第 231 题 (Power of Two) Given an integer, write a function to determine if it is a power of two. 这个题目有个特别简单的解法.当然.可以独自想出这种方法可不简单.这样的方法可以作为一个知识点记住就好了. class Solution { public: bool isPowerOfTwo(int n) { if(n <= 0) return false; return !(n &…

题目传送门 /* 数学题:当有一个数开根号后是无理数,则No */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmath> #include <vector> #include <iostream> #include <string> #include <map> #include <set> using…

比赛快结束的适合看了一下D题,发现跟前几天刚刚做过的HDU 5728 PowMod几乎一模一样,当时特兴奋,结果一直到比赛结束都一直WA.回来仔细一琢磨才发现,PowMod这道题保证了n不含平方因子,而Easy Math却没有.只要加一条特判,这道题就过了. AC代码贴在下面.求莫比乌斯函数前缀和的那一部分是我当时在网上临时找的代码,向那位仁兄道谢. #include<bits/stdc++.h> using namespace std; #define rep(i,a,b) for(int…

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 循环 递归 取对数 判断是不是最大3的倍数的因子 日期 [LeetCode] 题目地址:https://leetcode.com/problems/power-of-three/ Total Accepted: 38705 Total Submissions: 105634 Difficulty: Easy 题目描述 Given an integer…

原题: 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? 这个题目本身没有任何难度,也是easy等级,但是题目要求不能使用循环和迭代,解法如下: import math class Solution(object): def isPowerOfThree(self, n):…

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? Credits:Special thanks to @dietpepsi for adding this problem and creating all test cases. 给一个整数,写一个函数来判断此数是不是3的次方…

题目描述: 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? 解题思路: 对给定的数求以3为底的对数,然后再将结果用于3的次幂,看是否与原来的数相同. 代码如下: public class Solution { public boolean isPowerOfThree(in…

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, write a function to determine if it is a power of three. Follow up: Could you do it without using any loop / recursion? (二)解题 题目大意:判断一个是不是3…

Problem: Given an integer, write a function to determine if it is a power of three. Could you do it without using any loop / recursion? Summary: 用非循环/递归的方法判断数n是否为3的整数幂. Analysis: 1. 循环:将n逐次除以3,判断是否为3的整数幂. class Solution { public: bool isPowerOfThree(…

翻译 给定一个整型数,写一个函数决定它是否是3的幂(翻译可能不太合适-- 跟进: 你能否够不用不论什么循环或递归来完毕. 原文 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? 分析 题意我事实上不是满懂,比方说12究竟可不能够呢?还是说仅仅有:3.9.27.81这样的才行…

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…

判断一个数是否是3的n次幂 这里我用了一点巧,所有的int范围的3的n次幂是int范围最大的3的n次幂数(即3^((int)log3(MAXINT)) =  1162261467)的约数 这种方法是我目前觉得是最好的,不容易出错,其他的方法因为精度问题而很容易错. class Solution { public: bool isPowerOfThree(int n) { ) %n==; else return false; } };…

本博客是个人原创的针对leetcode上的problem的解法,所有solution都基本通过了leetcode的官方Judging,个别未通过的例外情况会在相应部分作特别说明. 欢迎互相交流! email: tomqianmaple@gmail.com 后续更多的easy题已经不属于Top Interview Questions,所以现在就不集中精力去做了,只做到目前的100题左右. Palindrome Linked List Lowest Common Ancestor of a Bina…

LeetCode 第 342 题(Power of Four) 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? 题目非常eas…

本博客是个人原创的针对leetcode上的problem的解法,所有solution都基本通过了leetcode的官方Judging,个别未通过的例外情况会在相应部分作特别说明. 欢迎互相交流! email: tomqianmaple@gmail.com Two Sum Reverse Integer Palindrome Number Roman to Integer Longest Common Prefix Valid Parentheses Merge Two Sorted Lists…

/* 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?*/ public class PowerOfThree { private static final double EX=10e-15; public static void main(String[] args) {…

 *勿以浮沙筑高台* 持续更新........     题目网址:https://leetcode.com/problemset/all/?difficulty=Easy 1. Two Sum [4ms] 2. Reverse Integer [12ms] 题意:将一个32bit signed integer反转输出,如果反转之后超出32位补码范围 [-2^31,2^31-1],则输出0 思路:边取模边算结果,结果存longlong判界 3. Palindrome Number [112ms]…

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…

1. Two Sum Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution. Example: Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + n…

leetcode 34 最早出现和最后出现 class Solution { public int[] searchRange(int[] nums, int target) { int []ans={-1,-1} ; for(int i=0;i<nums.length;i++){ if(nums[i]==target){ ans[0]=i; break; } } for(int j=nums.length-1;j>=0;j--){ if(nums[j]==target){ ans[1]=j;…

前言:这是关于LeetCode上面练习题C++的笔记,有些地方参考有网友的解题方法(可能有些参考没能注明,望谅解),如有需要改进的地方希望留言指教,多谢! 目录: ZigZag Conversion Reverse digits of an integer Implement atoi to convert a string to an integer Determine whether an integer is a palindrome Write a function to find th…

给出一个整数,写一个函数来确定这个数是不是3的一个幂.后续挑战:你能不使用循环或者递归完成本题吗? 详见:https://leetcode.com/problems/power-of-three/description/ C++: 方法一: class Solution { public: bool isPowerOfThree(int n) { while(n&&n%3==0) { n/=3; } return n==1; } }; 方法二: class Solution { publi…