263. Ugly Number

Easy

An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.

Given an integer n, return true if n is an ugly number.

Example 1:

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

Example 2:

Input: n = 1
Output:
 true
Explanation:
 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.

Example 3:

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

Constraints:

• -231 <= n <= 231 - 1

解題

func isUgly(n int) bool {
    if n < 1 { return false }

    for n % 2 == 0 {
        n /= 2
    }

    for n % 3 == 0 {
        n /= 3
    }

    for n % 5 == 0 {
        n /= 5
    }

    return n == 1
}