chess bishops on a $100 \times 100$ chess board.
Source: 45th International Tournament of Towns, Junior A-Level P7, Fall 2023
December 16, 2023
combinatorics
Problem Statement
7. There are 100 chess bishops on white squares of a chess board. Some of them are white and some of them are black. They can move in any order and capture the bishops of opposing color. What number of moves is sufficient for sure to retain only one bishop on the chess board?