263. Ugly Number - easy
문제
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.
제한사항
- 1 is typically treated as an ugly number.
- Input is within the 32-bit signed integer range: [−231, 231 − 1].
입출력 예
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Example 1:
Input: 6
Output: true
Explanation: 6 = 2 × 3
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Example 2:
Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
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Example 3:
Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7.
풀이
- math
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func isUgly(num int) bool {
if (num == 0) {
return false
} else if (num == 1 || num == 2 || num == 3 || num == 5) {
return true;
}
res := false
if (num % 2 == 0) {
res = res || isUgly(num/2)
}
if (num % 3 == 0) {
res = res || isUgly(num/3)
}
if (num % 5 == 0) {
res = res || isUgly(num/5)
}
return res
}