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Passing Coins Around a Round Table

Source: CentroAmerican 2013 Problem 2

August 24, 2013
combinatorics unsolvedcombinatoricsProcesses

Problem Statement

Around a round table the people P1,P2,...,P2013P_1, P_2,..., P_{2013} are seated in a clockwise order. Each person starts with a certain amount of coins (possibly none); there are a total of 1000010000 coins. Starting with P1P_1 and proceeding in clockwise order, each person does the following on their turn:
[*]If they have an even number of coins, they give all of their coins to their neighbor to the left.
[*]If they have an odd number of coins, they give their neighbor to the left an odd number of coins (at least 11 and at most all of their coins) and keep the rest.
Prove that, repeating this procedure, there will necessarily be a point where one person has all of the coins.