2012 ToT Spring Senior O p2 no 1,2,...,, n, -n,..., -2, -1 in a 1x 2n board
Source:
March 5, 2020
primecombinatoricstablerectangle table
Problem Statement
The cells of a 1\times 2n board are labelled from left to right. A marker is placed on an arbitrary cell. If the label of the cell is positive, the marker moves to the right a number of cells equal to the value of the label. If the label is negative, the marker moves to the left a number of cells equal to the absolute value of the label. Prove that if the marker can always visit all cells of the board, then is prime.