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Spain Mathematical Olympiad
2020 Spain Mathematical Olympiad
4
4
Part of
2020 Spain Mathematical Olympiad
Problems
(1)
Adding game.
Source: Spain Mathematical Olympiad 2020 P4
7/15/2020
Ana and Benito play a game which consists of
2020
2020
2020
turns. Initially, there are
2020
2020
2020
cards on the table, numbered from
1
1
1
to
2020
2020
2020
, and Ana possesses an extra card with number
0
0
0
. In the
k
k
k
-th turn, the player that doesn't possess card
k
ā
1
k-1
k
ā
1
chooses whether to take the card with number
k
k
k
or to give it to the other player. The number in each card indicates its value in points. At the end of the game whoever has most points wins. Determine whether one player has a winning strategy or whether both players can force a tie, and describe the strategy.
Spain
combinatorics
game