Operations on Pebbles
Source: ISL 2022 C6
July 9, 2023
combinatoricsIMO ShortlistAZE IMO TST
Problem Statement
Let be a positive integer. We start with piles of pebbles, each initially containing a single pebble. One can perform moves of the following form: choose two piles, take an equal number of pebbles from each pile and form a new pile out of these pebbles. Find (in terms of ) the smallest number of nonempty piles that one can obtain by performing a finite sequence of moves of this form.