Find the Lexicographically Largest String From the Box II

Statement

You are given a string, word, and an integer numFriends, representing the number of friends participating in a game organized by Alice.

The game consists of multiple rounds, and in each round:

• The string word is split into exactly numFriends non-empty substrings.

• The split must be unique; no previous round has produced the same sequence of splits.

• All resulting substrings from the split are placed into a box.

When all rounds are over and all possible unique splits have been performed, determine the lexicographically largest string among all the substrings in the box.

A string $a$ is considered lexicographically larger than a string $b$ ...