Cherry Pickup II

Two robots start at the top-left and top-right of an rows×cols grid and simultaneously move down one row each step choosing left/stay/right (col-1/col/col+1), collecting cherries (counted once if both land on the same cell); compute the maximum cherries they can collect when both reach the bottom. The core challenge is maximizing combined reward over paired robot positions per row, typically solved with a DP over (row, col1, col2) under rows,cols ≤ 70.