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.
Example 1:
Input: 6 Output: true Explanation: 6 = 2 × 3 Example 2: Input: 8 Output: true Explanation: 8 = 2 × 2 × 2 Example 3: Input: 14 Output: false Explanation: 14 is not ugly since it includes another prime factor 7.看num是否可以被2整除，如果可以，不断除以2. 然后看能否被3整除，如果可以，不断除以3. 然后看能否被5整除，如果可以，不断除以5.
最后得到一个数，看它是否为1.
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; } }