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.

class Solution {
public:
    bool isUgly(int num) {
        if(num==0)
        return false;
        if(num==1 || num==2 || num==3 || num==5)
        return true;
        if(num%2==0)
        return isUgly(num/2);
        if(num%3==0)
        return isUgly(num/3);
        if(num%5==0)
        return isUgly(num/5);
        return false;
    }
};
posted @ 2015-11-28 16:03  djiankuo  阅读(125)  评论(0编辑  收藏  举报