You are given a list of three-digit integers representing a binary tree's structure and node values. Calculate the sum of all paths from the root to the leaves in this tree.

Given an array of integers, determine if it's possible to split it into two non-empty subarrays with equal sums. The split point itself is not included in either subarray's sum.

You are given a list of strings. Concatenate them to form a single string, then find the lexicographically largest string possible by splitting the concatenated string at any point and rejoining it.