Question

2413. Smallest Even Multiple

中文文档

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

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;
  }
};

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
  }
}

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