MathDB
Moving checkers by a given rule to finally reverse the order

Source: ToT 2003-JO-5

June 18, 2011
combinatorics unsolvedcombinatorics

Problem Statement

2525 checkers are placed on 2525 leftmost squares of 1×N1 \times N board. Checker can either move to the empty adjacent square to its right or jump over adjacent right checker to the next square if it is empty. Moves to the left are not allowed. Find minimal NN such that all the checkers could be placed in the row of 2525 successive squares but in the reverse order.