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2022-IMOC
C1
C1
Part of
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Problems
(1)
poor pigeon's egg got eaten by seagull
Source: 2022 IMOC C1
9/5/2022
Given a positive integer
k
k
k
, a pigeon and a seagull play a game on an
n
×
n
n\times n
n
×
n
board. The pigeon goes first, and they take turns doing the operations. The pigeon will choose
m
m
m
grids and lay an egg in each grid he chooses. The seagull will choose a
k
×
k
k\times k
k
×
k
grids and eat all the eggs inside them. If at any point every grid in the
n
×
n
n\times n
n
×
n
board has an egg in it, then the pigeon wins. Else, the seagull wins. For every integer
n
≥
k
n\geq k
n
≥
k
, find all
m
m
m
such that the pigeon wins.Proposed by amano_hina
combinatorics
IMOC