263. Ugly Number

Ugly Number

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.

Solution

public class Solution {
       public boolean isUgly(int num) {
                   if (num == 0) return false;

        while (num % 2 == 0) {
            num /= 2;
        }

        while (num % 3 == 0) {
            num /= 3;
        }

        while (num % 5 == 0) {
            num /= 5;
        }

        return num == 1;
    }
}