Ugly Number.md

#Ugly Number ##Problem: 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. ##Idea: Decomposition of prime factors

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