README.md

263. 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.

Example 1:

Input: 6
Output: true
Explanation: 6 = 2 × 3

Example 2:

Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2

Example 3:

Input: 14
Output: false 
Explanation: 14 is not ugly since it includes another prime factor 7.

Note:

1. 1 is typically treated as an ugly number.
2. Input is within the 32-bit signed integer range: [−231, 231 − 1].

Solutions (Java)

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

Solutions (Python)

class Solution:
    def isUgly(self, n: int) -> bool:
        if n == 0: return False
        if n == 1: return True 
        if n % 2 == 0:
            return self.isUgly(n // 2)
        if n % 3 == 0:
            return self.isUgly(n // 3)
        if n % 5 == 0:
            return self.isUgly(n // 5)
        return False