# 2413. Smallest Even Multiple

## Description

Given a positive integer n, return the smallest positive integer that is a multiple of both 2 and n.

Example 1:

Input: n = 5
Output: 10
Explanation: The smallest multiple of both 5 and 2 is 10.


Example 2:

Input: n = 6
Output: 6
Explanation: The smallest multiple of both 6 and 2 is 6. Note that a number is a multiple of itself.


Constraints:

• 1 <= n <= 150

## Solutions

Solution 1: Mathematics

If $n$ is even, then the least common multiple (LCM) of $2$ and $n$ is $n$ itself. Otherwise, the LCM of $2$ and $n$ is $n \times 2$.

The time complexity is $O(1)$.

• class Solution {
public int smallestEvenMultiple(int n) {
return n % 2 == 0 ? n : n * 2;
}
}

• class Solution {
public:
int smallestEvenMultiple(int n) {
return n % 2 == 0 ? n : n * 2;
}
};

• class Solution:
def smallestEvenMultiple(self, n: int) -> int:
return n if n % 2 == 0 else n * 2


• func smallestEvenMultiple(n int) int {
if n%2 == 0 {
return n
}
return n * 2
}

• function smallestEvenMultiple(n: number): number {
return n % 2 === 0 ? n : n * 2;
}


• impl Solution {
pub fn smallest_even_multiple(n: i32) -> i32 {
if n % 2 == 0 {
return n;
}
n * 2
}
}