Smallest Even Multiple

Problem Description

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

Example

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

Solution Approach

Intuition:

To efficiently determine the smallest even multiple

Solution Implementation

Code In Different Languages:

JavaScript

Written by @Ishitamukherjee2004

 class Solution {
smallestEvenMultiple(n) {
 for (let i = 1; i <= 2 * n; i++) {
   const multiply = n * i;
   if (multiply % 2 === 0) {
     return multiply;
   }
 }
 return -1;
}
}

TypeScript

Written by @Ishitamukherjee2004

 class Solution {
smallestEvenMultiple(n: number): number {
 for (let i = 1; i <= 2 * n; i++) {
   const multiply = n * i;
   if (multiply % 2 === 0) {
     return multiply;
   }
 }
 return -1;
}
}

Python

Written by @Ishitamukherjee2004

 class Solution:
 def smallestEvenMultiple(self, n: int) -> int:
     for i in range(1, 2 * n + 1):
         multiply = n * i
         if multiply % 2 == 0:
             return multiply
     return -1

Java

Written by @Ishitamukherjee2004

 public class Solution {
 public int smallestEvenMultiple(int n) {
     for (int i = 1; i <= 2 * n; i++) {
         int multiply = n * i;
         if (multiply % 2 == 0) {
             return multiply;
         }
     }
     return -1;
 }
}

C++

Written by @Ishitamukherjee2004

class Solution {
public:
 int smallestEvenMultiple(int n) {
     for(int i=1; i<=2*n; i++){
         int multiply = n*i;
         if(multiply%2==0) {
             return multiply;
             break;

         }
     }
     return -1;
 }
};

Complexity Analysis

• Time Complexity: $O(2*n)$
• Space Complexity: $O(1)$
• The time complexity is $O(2*n)$ because we are iterating from 1 to 2*n.
• The space complexity is $O(1)$ because we are not using any extra space.