LeetCode -- Ugly Number

LeetCode -- Ugly Number

題目描述：




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.


判斷一個數是否為ugly number。


對2,3,5執行以下過程：
不斷除n，直到無法整除。


最後剩余數字為1，則該數為ugly number。






實現代碼：

public class Solution {
    public bool IsUgly(int num) 
    {
        if(num <= 0){
            return false;
        }
        num = Divide(num,2);
    	num = Divide(num,3);
    	num = Divide(num,5);
    	
    	return num == 1;
    }


private int Divide(int num, int a)
{
	while(num % a == 0){
		num /= a;
	}
	return num;
}


}