MathDB
Colouring the grid for points

Source: BdMO 2023 Secondary National P10 Higher Secondary National P8

February 12, 2023
combinatoricsgrid

Problem Statement

Joy has a square board of size n×nn \times n. At every step, he colours a cell of the board. He cannot colour any cell more than once. He also counts points while colouring the cells. At first, he has 00 points. Every step, after colouring a cell cc, he takes the largest possible set SS that creates a "++" sign where all cells are coloured and cc lies in the centre. Then, he gets the size of set SS as points. After colouring the whole n×nn \times n board, what is the maximum possible amount of points he can get?
Back to ProblemsView on AoPS