LeetCode_263. Ugly Number

 

263. Ugly Number

Easy

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:  is not ugly since it includes another prime factor .
147

Note:

1. 1 is typically treated as an ugly number.
2. Input is within the 32-bit signed integer range: [−231,  231 − 1].

 

package leetcode.easy;

public class UglyNumber {
	public boolean isUgly(int num) {
		if (num <= 0) {
			return false;
		}
		while (num % 2 == 0) {
			num = num / 2;
		}
		while (num % 3 == 0) {
			num = num / 3;
		}
		while (num % 5 == 0) {
			num = num / 5;
		}
		return num == 1;
	}

	@org.junit.Test
	public void test() {
		System.out.println(isUgly(6));
		System.out.println(isUgly(8));
		System.out.println(isUgly(14));
		System.out.println(isUgly(0));
	}
}