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.

Determine if a string containing parentheses and asterisks is a valid parenthesis string. The asterisk can represent a left parenthesis, a right parenthesis, or an empty string.

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.