Max Sliding Window Sum

Problem Description

Given an array of integers and a positive integer k, write a function that returns the maximum sum of any contiguous subarray of length k.

If the length of the array is less than k, the function should return null (or an equivalent value based on your language) since no valid subarray exists.

Example

For example, given the array [2, 3, 4, 1, 5] and k = 3, the contiguous subarrays of length 3 are:

• [2, 3, 4] with a sum of 9
• [3, 4, 1] with a sum of 8
• [4, 1, 5] with a sum of 10

The function should therefore return 10.

Special Note

On April 4th, many cultures celebrate renewal and new beginnings. This problem is a great way to refresh your algorithm skills by exploring a common sliding window technique.

Starter Code

Below is some starter code for various programming languages to help you begin your solution.