263. 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.

思路：
丑数，只包含因子2、3、5的数叫丑数

Java 代码（程序写得不好）：

public class Solution {
    public boolean isUgly(int num) {
        int[] arr = {2, 3, 5};
        while(num > 1) {
            int i = 0;
            for(; i < 3; i++) {
                if(num % arr[i] == 0) {
                    num /= arr[i];
                    break;
                }
            }
            if(i == 3) {
                return false;
            }
        }
        return num == 1;
    }
}