olymmath

ISL 2010 C4

Six stacks S1,…,S6S_{1}, \ldots, S_{6} of coins are standing in a row. In the beginning every stack contains a single coin. There are two types of allowed moves: Move 1: If stack SkS_{k} with 1≤k≤51 \leq k \leq 5 contains at least one coin, you may remove one coin from SkS_{k} and add two coins to Sk+1S_{k+1}. Move 2: If stack SkS_{k} with 1≤k≤41 \leq k \leq 4 contains at least one coin, then you may remove one coin from SkS_{k} and exchange stacks Sk+1S_{k+1} and Sk+2S_{k+2}. Decide whether it is possible to achieve by a sequence of such moves that the first five stacks are empty, whereas the sixth stack S6S_{6} contains exactly 2010201020102010^{2010^{2010}} coins. Same as Problem C4, but the constant 2010201020102010^{2010^{2010}} is replaced by 201020102010^{2010}. (Netherlands)

Dataset text NuminaMath olympiads. Quoted with source.

Official text: IMO 2010 Shortlist booklet, page 31.

Solutions

Official solution Solution 1 by the IMO Problem Selection Committee

The terms of the source let olymmath link to this solution but not copy it. Read the solution (IMO official site).

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