source: https://leetcode.com/problems/maximum-twin-sum-of-a-linked-list/description/ Maximum Twin Sum of a Linked List In a linked list of size n, where n is even, the ith node (0-indexed) of the linked list is known as the twin of the (n-1-i)th node, if 0 <= i <= (n / 2) – 1. For example, if n = 4, then node ...