Problem #PRU-65400

Problemas Problemas divertidos Problemas de palabras Tablas y torneos Tableros de ajedrez y piezas de ajedrez Métodos Ejemplos y contraejemplos. Pruebas constructivas Principio del casillero Principio del casillero (otros)

Problem

What is the smallest number of cells that can be chosen on a \(15\times15\) board so that a mouse positioned on any cell on the board touches at least two marked cells? (The mouse also touches the cell on which it stands.)