leetcode-java-326. Power of Three

/*Given an integer, write a function to determine if it is a power of three.1.递归2.数学方法x = log(n)/log(3),x是整数就可以了--那么判断整数方法：double类型，则绝对值差小于10e-15；floor类型，则绝对值差小于10e-6 */ public class Solution {     public boolean isPowerOfThree(int n) {         if(n == 1) {             return true;         } else if(n == 0) {             return false;         } else if(n % 3 == 0) {             return isPowerOfThree(n/3);         } else {             return false;         }     } } public class Solution {     public boolean isPowerOfThree(int n) {         if(n == 0) {             return false;         }         double x = Math.log(n)/Math.log(3);         return Math.abs(x - Math.round(x)) < 10e-15;     } }