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.

 

解题思路：

水题、、、、、

class Solution { public:     bool isUgly(int num) {         if(num<1)return false;         // 4ms         while((num&1)==0)num>>=1;         // 8ms         //while((num%2)==0)num/=2;         while(num%3==0)num/=3;         while(num%5==0)num/=5;         return num==1;     } };