There are few ways to do this, it depends in the number of variants.
- Equality of tournament - If want all winning competitors to play the same number of matches at any stage. On Tennis tournament every player will play the same number of games at every stage. This is in opposed to FA cup or UEFA companionship league qualifications round where higher ranked competitor will play less than others (referred to as bye).
- Competitors per match - most of sports are 2 competitors per match but it can be different like in Poker tournament.
On "Equal tournament", Assuming N competitors per match, the number of competitor need to be a power of N and there will be Log N NumberOfCompetitors rounds.
- Consolation stage - Some tournament has a second-change option e.g. Olympic Judo when a competitor loses on advanced rounds he gets second change throw consolation stage where he can still win bronze medal, It also exist in tournament that the third place is decided in a match between the semi-final losers.
- Re-seeding - Is there a Re-seeding after every round? e.g on NFL and NHL a Re-seeding occurs so the highest winning seed will be drawn against the lowest winning seed, the second-highest will meet the second-lowest, etc.
- Any other restrictions like (e.g competitor from the same state\league can't be drawn together)
Here are examples for several ways to determine seeded knockout features:
Regular Equal seeding tournament when the highest ranked competitor will be drawn against the lowest, the second-best against the second-worst and so on.
The second round will face the winner between the highest ranked and the lower will play against the winner between the two medium ranked competitor, Take a look at the following example from Wiki:
NBA Playoffs - As above but two tournament that divided to East and West conference, The championship is determine in a final between two winners.
Grand-slam Tennis -
1st and 2nd seeds are placed in separate brackets, but then the 3 and 4
seeds are assigned to their brackets randomly, and so too are seeds 5
through 8, and so on. This may result in some brackets consisting of
stronger players than other brackets, and since only the top 32
players are seeded at all in Tennis Grand Slam tournaments, it is
conceivable that the 33rd-best player in a 128-player field could end
up playing the top seed in the first round.
knockout tournament with pairings for each round
drawn at random. There are no seeds and the draw for each round is not
made until after the scheduled dates for the previous round. The draw
also determines which teams will play at home.
There are a total of 14 rounds in the competition — six qualifying
rounds, followed by six further rounds (the "proper" rounds),
semi-finals, and the final. The competition begins Extra Preliminary
Round, followed by the Preliminary Round and First Qualifying Round,
which are contested by the lowest-ranked clubs. Clubs playing in the
Conference North and Conference South are given exemption to the
Second Qualifying Round, and Conference National teams are given
exemption to the Fourth Qualifying Round. The 32 winners from that
round join the 48 clubs from League One and League Two in the First
Round (often called the First Round Proper). Finally, teams from the
Premier League and Football League Championship enter at the Third
Round Proper, at which point there are 64 teams remaining in the
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