263. Ugly Number（C++）

题目：

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；
丑数：因子只含有2、3、5.规定1是丑数，（0不是丑数，题目没说）

解答：

bool isUgly(int num) {    if(num==0)return false;    while(num%2==0){        num/=2;    }    while(num%3==0){        num/=3;    }    while(num%3==0){        num/=3;    }    return num==1;}//当然也有代码量更是少的，就用数字合并的思想bool isUgly(int num){    if(num>0){        for(int i=2;i<6;i++){            while(num%i==0){                num/=i;            }        }    }    return num==1;}