【LeetCode OJ 263】Ugly Number

【LeetCode OJ 263】Ugly Number

題目：Write a program to check whether a given number is an ugly number.

Ugly numbers are positive numbers whose prime factors only include2, 3, 5. For example,6, 8are ugly while14is not ugly since it includes another prime factor7.

Note that1is typically treated as an ugly number.

解題思路：上述題意表示，丑數的含義是其因子只包含2,3,5，判斷一個數是否為丑數，只需要將這個數與2,3,5循環相除，如果余數為1，則為丑數，否則不是。

示例代碼：

public 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;
	        if (num == 1) 
	        {
	            return true;
	        } 
	        else
	        {
	            return false;
	        }
	  }
}