Advent calendar 2022
21 December
In the annual tournament of Christmas puzzles, each player must play one puzzle match
against each other player. Last year there were four entrants into the tournament (A, B, C, and D),
and so 6 matches were played: A vs B, C vs D, A vs D, A vs C, D vs B, and finally B vs C.
This year, the tournament has grown in popularity and 22 players have entered. How many
matches will be played this year?