Ugly Number

Question

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 l are ugly while 14 is not ugly since it includes another prime factor 7 .

Notice
Note that 1 is typically treated as an ugly number.

Solution

Java

public class Solution {
    /**
     * @param num an integer
     * @return true if num is an ugly number or false
     */
    public boolean isUgly(int num) {
        // Write your code here
        if (num < 1) {
            return false;
        }
        if (num == 1) {
            return true;
        }
        while (num % 5 == 0) {
            num = num / 5;
        }
        while (num % 3 == 0) {
            num = num / 3;
        }
        while (num % 2 == 0) {
            num = num / 2;
        }
        if (num == 1) {
            return true;
        }
        return false;
    }
}