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.

判断一个数是不是丑数

C++（3ms）：

class Solution {
public:
    bool 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 ;
        return num == 1 ;
    }
};

java(2ms):

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 ;
        return num == 1 ;
    }
}