MathDB

Consider a table with

n

rows and

2n

columns. we put some blocks in some of the cells. After putting blocks in the table we put a robot on a cell and it starts moving in one of the directions right, left, down or up. It can change the direction only when it reaches a block or border. Find the smallest number

m

such that we can put

m

blocks on the table and choose a starting point for the robot so it can visit all of the unblocked cells. (the robot can't enter the blocked cells.)
Proposed by Seyed Mohammad Seyedjavadi and Alireza Tavakoli

11

Problems(1)