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.
丑数的计算，分别去除数字中的2，3，5部分，如果数字被整除了那么就是丑数，否则不是，下见代码：
1 class Solution { 2 public: 3 bool isUgly(int num) { 4 if(num == 0) 5 return false; 6 while(num % 2 == 0) num /= 2;//exclude 2 factor 7 while(num % 3 == 0) num /= 3;//exclude 3 factor 8 while(num % 5 == 0) num /= 5;//exclude 5 factor 9 return (num == 1);//is Ugly 10 } 11 };
java版本如下所示，方法相同：
public class Solution { public boolean 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; } }