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National and Regional Contests
Korea Contests
Korea Junior Mathematics Olympiad
2023 Korea Junior Math Olympiad
4
4
Part of
2023 Korea Junior Math Olympiad
Problems
(1)
Tennis tournament
Source: KJMO 2023 P4
11/4/2023
2023
2023
2023
players participated in a tennis tournament, and any two players played exactly one match. There was no draw in any match, and no player won all the other players. If a player
A
A
A
satisfies the following condition, let
A
A
A
be "skilled player".(Condition) For each player
B
B
B
who won
A
A
A
, there is a player
C
C
C
who won
B
B
B
and lost to
A
A
A
. It turned out there are exactly
N
(
≥
0
)
N(\geq 0)
N
(
≥
0
)
skilled player. Find the minimum value of
N
N
N
.
combinatorics