Introduction

In this blog post, we will explore how to solve the LeetCode problem "2413" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

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

Explanation

Here's the solution to find the smallest positive integer that is a multiple of both 2 and n:

• Key Idea: The problem asks for the Least Common Multiple (LCM) of 2 and n. However, since we know one of the numbers is 2, a simplified approach is sufficient.
• Optimization: If n is even, it's already a multiple of 2. Otherwise, we just need to multiply n by 2.

• Direct Calculation: This avoids unnecessary calculations like finding the Greatest Common Divisor (GCD) and then using the LCM = (n1 * n2) / GCD formula.

• Complexity: O(1) runtime, O(1) storage.

Code

    def smallest_multiple(n: int) -> int:
    """
    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
    """
    if n % 2 == 0:
        return n
    else:
        return n * 2