Leetcode50: 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.

根据丑数的定义，丑数只能被2、3和5整除。也就是说我们把它连续除以2，再连续除以3，再连续除以5，如果最后我们得到的是1，那么这个数就是丑数，否则不是。

class Solution {public:    bool isUgly(int num) {        if(num <= 0)            return false;                while(num%2 == 0)        {            num /= 2;        }                while(num%3 == 0)        {            num /= 3;        }                while(num%5 == 0)        {            num /= 5;        }                return (num == 1) ? true:false;    }};