Problem #PRU-97991

Problemas Problemas divertidos Problemas de palabras Tablas y torneos Tableros de ajedrez y piezas de ajedrez

Problem

What is the minimum number of squares that need to be marked on a chessboard, so that:

1) There are no horizontally, vertically, or diagonally adjacent marked squares.

2) Adding any single new marked square breaks rule 1.