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
}