Problem Statement

Cherry Pickup You are given an n x n grid representing a field of cherries. Each cell holds one of three integers: 0 means the cell is empty, so you can pass through it, 1 means the cell contains a cherry that you pick up as you pass through it, -1 means the cell contains a thorn that blocks your way. Collect as many cherries as you can by following these rules: Start at (0, 0) and reach (n - 1, n - 1) by moving right or down through valid path cells (cells with value 0 or 1 ). After reaching (n - 1, n - 1) , return to (0, 0) by moving left or up through valid path cells. When you pass through a path cell containing a cherry, you pick it up and the cell becomes an empty cell 0 . A cherry can therefore be collected only once, even if both legs of the round trip cross that cell. If there is no valid path between (0, 0) and (n - 1, n - 1) , then no cherries can be collected and the answer is 0 . Return the maximum number of cherries you can collect. Function Description Complete the funct