326.md

326. Power of Three

Description

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?

Solution

Solution 1

/**
 * @param {number} n
 * @return {boolean}
 */
var isPowerOfThree = function(n) {
    "use strict";
    if (n === 0) {
        return false;
    }
    while (n !== 1) {
        n /= 3;
        if (!Number.isInteger(n)) {
            return false;
        }
    }
    return true;
};

Solution 2

/**
 * @param {number} n
 * @return {boolean}
 */
var isPowerOfThree = function(n) {
    "use strict";
    let str = n.toString(3);
    str = str.replace(/0/g, "");
    return str === "1";
};