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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 \(O(1)\).

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

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

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

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

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

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

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

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