Ugly Number 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
Ugly Number Solutions
✅Time: O(log n)
✅Space: O(1)
C++
class Solution {
public:
bool isUgly(int n) {
if (n == 0)
return false;
for (const int prime : {2, 3, 5})
while (n % prime == 0)
n /= prime;
return n == 1;
}
};
Java
class Solution {
public boolean isUgly(int n) {
if (n == 0)
return false;
for (final int prime : new int[] {2, 3, 5})
while (n % prime == 0)
n /= prime;
return n == 1;
}
}
Python
class Solution:
def isUgly(self, n: int) -> bool:
if n == 0:
return False
for prime in 2, 3, 5:
while n % prime == 0:
n //= prime
return n == 1
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