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/**

* 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.

*

* Note:

* 1 is typically treated as an ugly number.

* Input is within the 32-bit signed integer range: [−231, 231 − 1].

*/

public class UglyNumber263 {

public boolean isUgly(int num) {

if (num == 1) return true;

if (num <= 0) return false;

int n = num;

if (num % 2 == 0) num /= 2;

if (num % 3 == 0) num /= 3;

if (num % 5 == 0) num /= 5;

if (num == n) return false;

return isUgly(num);

}

public boolean isUgly2(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;

}

}