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.
思路：按定义做。
代码：
1 class Solution { 2 public: 3 bool isUgly(int num) { 4 if(num<=0){ 5 return false; 6 } 7 while(num%2==0){ 8 num=num>>1; 9 } 10 while(num%3==0){ 11 num/=3; 12 } 13 while(num%5==0){ 14 num/=5; 15 } 16 return num==1; 17 } 18 };
原文：http://www.cnblogs.com/Deribs4/p/5671866.html