leetcode-263-ugly number

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.

Credits:

丑数是指那些只有2，3，5作为质因子的数字，判断一个数是不是丑数。

循环剔除所有2，3，5因子，看剩下的是否是1.

class Solution {
    public:
        bool isUgly(int num) {
            if(num==0) return false;
            while(num%5==0)
                num/=5;
            while(num%3==0)
                num/=3;
            while(num%2==0)
                num/=2;
            return num==1;

    }
};