In comparison with O-Level problems, problems of P-level are easier; the hardest one is 4 points worth. Time of Contest: 3 hours, from 11:00 to 2:00, in BA 2175.
Coming in 10–15 minutes in advance is appreciated.

Deadlines for registration: P-Level Oct.9, O-Level Oct.16, A-Level Oct.23.

Sample Problems

Sample P-level Problem
Is it possible to move a Knight from square a1 to square h8 so that to visit each square of a chess board exactly ones? (Chessboard is a regular one and the Knight moves according to the chess rules).

Sample O-level Problem
A 9 × 9 chessboard with the standard checkered pattern has white squares at its four corners. What is the least number of rooks that can be placed on this board so that all the white squares are attacked? (A rook also attacks the square it is on, in addition to every other square in the same row or column).
(A rook also attacks the square it is on, in addition to every other square in the same row or column).

Sample A-level Problem
The spectators are seated in a row with no empty places. Each is in a seat which does not match the spectator's ticket. An usher can order two spectators in adjacent seats to trade places unless one of them is already seated correctly. Is it true that from any initial arrangement, the usher can place all the spectators in their correct seats?

Preparatory Sessions