【Leetcode】Ugly Number

题目链接：https://leetcode.com/problems/ugly-number/
题目：

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.

算法：

	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;

		if (num == 1) {
			return true;
		} else {
			return false;
		}
	}