Maximum Points Through Cards

There are several cards arranged in a row, and each card has an associated number of points. The points are given in the integer array cardPoints.

In one step, you can take one card from the beginning or from the end of the row. You have to take exactly k cards.

Your score is the sum of the points of the cards you have taken.

Given the integer array cardPoints of size n and the integer k, return the maximum score you can obtain.

Input format:

First parameter: Number n

Second parameter: Array cardPoints of Number of size n.

Third parameter: Number k

Output format:

Return the number

Example 1:

Input:
 7
 1 2 3 4 5 6 1 
 3
Output: 12
Explanation: After the first step, your score will always be 1. However, choosing the rightmost card first will maximize your total score. The optimal strategy is to take the three cards on the right, giving a final score of 1 + 6 + 5 = 12.

Example 2:

Input:
3
2 2 2
2
Output: 4
Explanation: Regardless of which two cards you take, your score will always be 4.

Constraints:

• 1 <= cardPoints.length <= 10⁵
• 1 <= cardPoints[i] <= 10⁴
• 1 <= k <= cardPoints.length
• Expected Time Complexity: O(n)
• Expected Space Complexity: O(1)