[LeetCode]Ugly Number

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.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

 

除2,3,5就好了。

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