Define a state representation for Sudoku answer search. A state is a partially filled, valid grid in which no rows, column, or 3x3 square contains duplicated digits. b. Write a pseudocode for the successor function (generate a list of successor states from the current state) given your representation. You can assume you have functions like "duplicated" that returns true if there are two identical non-empty elements (or non-zero digits) in a collection.