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.

　　丑數(shù)就是分解因子之后只含有2,3,5的數(shù)就是丑數(shù)，題目是判斷一個(gè)整數(shù)是不是丑數(shù)，簡(jiǎn)單到只有這一種解法，沒(méi)有別的了

My Solution

(Java) Version 1 Time: 2ms:

　　判斷性質(zhì)先跟著定義走，既然丑數(shù)是又2,3,5相乘得來(lái)的，那就除回去，先是用2除，除到除不盡了，就用3除，再用5除，如果是丑數(shù)的話，那肯定最后會(huì)得到1，那這就是丑數(shù)

public class Solution {
    public boolean isUgly(int num) {
        if(num==1||num==2||num==3||num==5)return true;
        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;
        return false;
    }
}