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? 大意: 给出一个数字(有符号32位),写一个函数来检查它是不是4的次方数。
这道题让我们判断一个数是否为4的次方数,那么最直接的方法就是不停的除以4,看最终结果是否为1,参见代码如下: 解法一: classSolution {public:boolisPowerOfFour(intnum) {while(num && (num %4==0)) { num/=4; }returnnum ==1; } }; 还有一种方法是跟Power of Three中的解法三一样,使用换底公式...
publicbooleanisPowerOfFour3(intnum){returnnum >0&& Integer.toString(num,4).matches("10*"); } 05 第四种解法 将4的所有幂次方整数放入一个HashSet中,然后判断num是否被包含在其中。 public boolean isPowerOfFour4(intnum) {Set<Integer>set=newHashSet<>(Arrays.asList(1,4,16,64,256,1024,4096,16...
LeetCode(65)-Power of Four 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?
(n & 0x55555555) != 0: 判断 n 的二进制位是否存在偶数位为 1 // // 当前仅当上述两个条件都满足时, n 是 4 的幂次方 return (n & (n - 1)) == 0 && n & 0x55555555 != 0 } 题目链接: Power of Four: leetcode.com/problems/p 计算布尔二叉树的值: leetcode.cn/problems/po Leet...
【Leetcode】Power of Four 题目链接:https://leetcode.com/problems/power-of-four/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....
英文网址:342. Power of Four。 中文网址:342. 4的幂。 思路分析 求解关键: 1、列出414 1、414 1、424 2、434 3等等,找出规律; 41=22=224 1 = 2 2 = 2 2,表示成二进制就是100100,11后面22个“00”; 42=(22)2=2442=(22)2=24,表示成二进制就是1000010000,11后面44个“00”; ...
leetcode.com/problems/power-of-three/ 2.1)采用循环 class Solution: def isPowerOfThree(self, n: int) -> bool: if not n: return False while n: if n==1: return True if n%3: return False n //=3 return True Runtime: 80 ms, faster than 52.08% of Python3 online submissions...
Power of Two Given an integer, write a function to determine if it is a power of two. 整除法 复杂度 时间O(1) 空间 O(1) 思路 最简单的解法,不断将原数除以2,一旦无法整除,余数不为0,则说明不是2的幂,如果整除到1,说明是2的幂。
Leetcode 231. Power of Two (Python) Myron_yoo 21 0 Leetcode刷题 2 两数相加 Add Two Numbers JS老毕 2257 4 Leetcode力扣22 手画图解版|括号生成Generate Parentheses 爱学习的饲养员 4029 4 一周刷爆LeetCode,算法大神左神(左程云)耗时100天打造算法与数据结构基础到高级全家桶教程,直击BTAJ等一线...