【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.

思路：

easy 时间复杂度O(n)

算法：

[java] view
plain copy

1. public boolean isUgly(int num) {
2. if (num <= 0) {
3. return false;
4. }
5. while (num % 2 == 0)
6. num /= 2;
7. while (num % 3 == 0)
8. num /= 3;
9. while (num % 5 == 0)
10. num /= 5;
11. if (num == 1) {
12. return true;
13. } else {
14. return false;
15. }
16. }