ugly-number.js

// Write a program to check whether a given number is an ugly number.
//
//
//
// Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.
//
//
//
// Note that 1 is typically treated as an ugly number.
//
//
// Credits:Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.


/**
 * @param {number} num
 * @return {boolean}
 */
var isUgly = function(num) {
    if (num <= 0) return false;
    if (num === 1) return true;
    while (num % 2 === 0) num /= 2;
    while (num % 3 === 0) num /= 3;
    while (num % 5 === 0) num /= 5;
    
    return num === 1;
};