LeetCode-326. Power of Three
Description:
Given an integer, write a function to determine if it is a power of three.
判断一个整数是否是3的幂。
基于公式log3^n可以得出y=lg(n)/log(3)如果y正好是个整数的话,说明n是3的幂。也可以使用循环除3的方法,也不是很浪费时间循环不了多少次。
public class Solution { public boolean isPowerOfThree(int n) { double ans = Math.log(n) / Math.log(3); return Math.abs(ans - Math.round(ans)) < 0.000000000001; } }
作者:Pickle
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