Is Smallest Even Multiple easy or hard?

Smallest Even Multiple is an Easy-level problem with an acceptance rate around 88%. The challenge is recognizing that the result equals LCM(n, 2), which reduces the solution to a simple even/odd check.

Smallest Even Multiple Python/Java solution

The core logic is identical across languages. In Python or Java, check if n % 2 == 0 and return n; otherwise return n * 2. Some implementations use (n & 1) to detect odd numbers with a bitwise operation.

How to solve Smallest Even Multiple in O(1)?

Check whether the number is even. If n is even, it already contains the factor 2 so the answer is n. If n is odd, multiply it by 2 to get the smallest even multiple. This constant-time check avoids loops or extra computations.

What is the best approach for Smallest Even Multiple?

The optimal approach checks whether n is even. If n % 2 == 0, return n; otherwise return 2 * n. This works because the problem is equivalent to computing LCM(n, 2). The algorithm runs in O(1) time and O(1) space.

Is Smallest Even Multiple asked at Google/Amazon/Meta?

This problem is categorized as an easy math and number theory question commonly used in coding platforms to test basic reasoning and edge-case handling. It is more typical in screening rounds or practice sets rather than advanced on-site interviews at companies like Google or Meta.

What data structure is used in Smallest Even Multiple?

No data structures are required. The solution relies purely on arithmetic and parity checks using modulo or bit manipulation, making it a straightforward math-based problem.

What is the time complexity of Smallest Even Multiple?

The solution runs in O(1) time because it performs only a constant number of operations: a parity check and possibly one multiplication. Space complexity is also O(1) since no additional data structures are required.

Description Hints 2 Solution Video 1:41

2413. Smallest Even Multiple

Easy88.5% acceptance4 companies

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

Asked at 4 companies

Google Amazon Meta Bloomberg

Topics

Math Number Theory

Hints open one at a time

Hint 1

A guaranteed way to find a multiple of 2 and n is to multiply them together. When is this the answer, and when is there a smaller answer?

Hint 2

There is a smaller answer when n is even.

1:41

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