263. Ugly Number 丑数

https://leetcode.com/problems/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){
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;
}
};

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;
}
};