There are three main ways to classify a tournament in Robot Battle: by what restrictions there are on the robots entered, by how many robots are entered as a unit, and how the robots (or groups of robots) are assigned ("paired") to fight each other in matches.
Robot Restrictions
The default for Robot Battle is that there are no restrictions on your robot's code. Of course, you must program your own robots: you can't enter someone else's robot.
Tiny Bot
Tiny bot tournaments restrict how large your robot's program may be in terms of bytes. Typically, you are limited to 500 bytes, although other sizes have been used in tournaments. The tournament should specify the byte limit.
Pithy Bot
Pithy bot tournaments restrict how large your robot's program may be in terms of words. A word is defined as a string of characters bounded by white space, shrunken logical operators, or any of the characters "{}()[]+-*/%&^|=<>!". The words 'and,' 'or,' 'endIf,' and 'endW' do not count. Typically you are limited to 66 words, but again the tournament should explicitly specify the word limit.
Neo
Neobyte or neoword tournaments are tiny bot and pithy bot tournaments, respectively. However the byte or word limit is on the team entered as a whole, and teams may have any number of robots. So in a neobyte tournament with a limit of 2000 bytes, you could have 4 robots of 500 bytes, 1 robot of 1000 bytes and 2 of 500 bytes, or 20 robots of 100 bytes, or any other combination that adds up to 2000 bytes.
Robot Units
Robots can be entered either singly or in teams. Often robots are entered as single units, but an author may enter more than one robot, and the robots can try and team up during the course of the match.
Pairings
Pairings is a general term for how robots are assigned to a match, even though there may be more than two robots in a given "pairing." For example, you could run a round robin where three robots fight against each other (with no teams). Every combination of three robots would be run.
AILO/AIFO
AILO is short for All In Last Out. In the first round, all of the robots fight together in one big battle. Whichever robot scores the lowest is removed from the tournament, and assigned last place. For the second round, the remaining robots are run in another big battle. Again, the lowest scoring robot is eliminated from the tournament, this time assigned next-to-last place. Each round, the lowest scoring robot is eliminated, and the remaining robots fight again, until there are only two robots left. The winner of the final two robot battle is the winner of the tournament.
AIFO is short for All In First Out, and is the reverse of an AILO. Each round the highest scoring robot is removed, until there are only two robots remaining. The loser of the last two robot battle is assigned last place. The winner of the AIFO is the winner of the first round.
The size of the arena generally shrinks as the number of robots shrink, so that there is a constant density of robots in the arena at the start of each match.
Dancing
Dancing tournaments do not involve robots fighting against each other. They involve a robot (or more often a team of robots) move around the arena in a coordinated fashion. Some method of "aesthetic" judgement is used to determine the winner of the tournament.
Rally Cup
A rally cup is a king of the hill tournament played in tiers. The top tier has one robot in it, the tier below it (the second tier) has two robots, and so on down, with each tier having one robot more than the tier above it. The bottom tier may not be full, depending on how many robots are entered into the tournament.
When a new robot enters the tournament, it is entered on the bottom tier. All the robots in a tier fight in one battle. The winner goes to the next tier. The winner and all the robots on the next tier fight a match, the winner again goes up to the next highest tier, and the loser drops down to the next lower tier. This process repeats all the way to the top. Then the winner of the second tier match fights the leader, who is alone on the first tier. Whoever loses drops back to the second tier.
Rally cups are generally run for a period of time, with rolling admissions. Player can even remove their robots from the tournament, and replace them with newer versions. Whoever is in the top tier when the tournament ends is the winner.
As with AILOs, rally cups generally change the size of the arena based on how many robots are fighting in the battle.
Round Robin
In a round robin tournament, every one plays everyone else. So if you have four robots, Attacker, Bouncer, Charger, and Dud, the matches played would be:
- Attacker v Bouncer
- Attacker v Charger
- Attacker v Dud
- Bouncer v Charger
- Bouncer v Dud
- Charger v Dud
In a team tournament, each team would face each other team in the same way. A one on one round robin is sometimes called a dogfight, and a two on two round robin is sometimes called a tag team or wingman tournament.
The winner is generally the robot that wins the most matches, with total number of games won as a tie breaker.
Single Eliminations
In a single elimination tournament, the robots are split up into pairs in the first round. The loser of each match is eliminated from the tournament. The winners are paired up against each other in the second round, and again the loser of each match is eliminated from the tournament. This continues until two robots are left. They fight each other and the winner wins the tournament.
If the number of robots entered is not a power of two, some robots will have to be given "byes," which means they do not have to play in the first round of the tournament.
Double Elimination
In a double elimination tournament it takes two losses to eliminate you from the tournament. Everyone starts in the winner's bracket. When you lose a match you go into the "loser's bracket." If you lose a match while in the loser's bracket, you are eliminated from the tournament. At the end, the winner of the winner's bracket and the winner of the loser's bracket face each other. Since the winner of the winner's bracket has not lost at this point, the winner of the loser's bracket must beat him twice in order to win the tournament. The winner of the winner's bracket only has to win once to win the tournament.
Traditionally, the loser bracket runs two rounds for every round of the winner's bracket. First, the winners of the last round of the loser's bracket are paired against the losers of the last round of the winner's bracket. Then the winners of those matches are paired against each other.
That should have confused you enough that you never want to run a double elimination tournament.
Triple Elimination
Triple elimination is basically run like double elimination, with a third bracket added for those who have lost twice. This tournament format is limited to people who aren't confused by the double elimination format.
Swiss System
The Swiss system is a variant of the round robin, that takes fewer rounds. Robots are paired off against each other in the first round, and are assigned a tournament score based on how they do in the match. In the second round, robots are paired against each other based on their tournament score: the winners fight the other winners, and the losers fight the other losers. Points are scored based on the second round matches, and added to the tournament score. Each succesive round robots are again paired based on there tournament score, generally with modifications made so that the same robots don't face each other twice in the same tournament.
A Swiss system is generally run for the same number of rounds as a single elimination tournament would be run with the same number of robots. The winner is the robot with the highest tournament score at the end of the tournament. There are different tie-breakers that can be used, most popular being sum of opponent's scores.
Swiss Elimination
Swiss elimination was made by people who don't think you can win if somebody else doesn't lose. A normal Swiss system tournament is run, as above, but usually for one or two rounds less than normal. Than the top four robots (or more in a large tournament) play in a single elimination tournament to determine the overall winner.