Cherry Pickup

Statement

You are given an $n \times n$ grid representing a field of cherries. Each cell in the grid can have one of three possible values:

• $0$: An empty cell that can be walked through

• $1$: A cell containing a cherry that can be picked and then passed through

• $-1$: A cell containing a thorn, which cannot be crossed

Your task is to find the maximum number of cherries that can be collected while following these rules:

1. Start at the top-left corner ...