[LeetCode]326. Power of Three

题目描述

思路

简单循环

代码

循环
暴力解
非循环
找出整数中最大的3的指数的数，则满足是三的指数的数，对他取模为0

class Solution {public:    bool isPowerOfThree(int n) {        if (n == 0)            return false;        while(n % 3 == 0)            n /= 3;        return n == 1;    }};

非循环

class Solution {public:    bool isPowerOfThree(int n) {        int Max3PowerInt = 1162261467; // 3^19, 3^20 = 3486784401 > MaxInt32        int MaxInt32 = 2147483647; // 2^31 - 1        if (n <= 0 || n > Max3PowerInt) return false;        return Max3PowerInt % n == 0;    }};