Round Robin - Lua

round-robin.lua

 --[[
  Round Robin
  Given 3 Teams (A, B, C), we want to organize a tournament schedule such that every team plays every other team exactly once. Here is a valid schedule for these 3 teams:

  A - B
  B - C
  A - C
  How about if we have N teams? Devise a general purpose algorithm that generates tournament schedules for N teams.
--]]

-- Solution (Lua)

function round_robin(...)
  local teams = {...}
  local count = 0

  while #teams > 1 do
    for i = 1, #teams - 1 do
      print(teams[1] .. ' vs. ' .. teams[i + 1])
      count = count + 1
    end
    table.remove(teams, 1)
  end
  print(count .. " games\n")
end

round_robin('Denver', 'New England')
round_robin('Denver', 'New England', 'Jacksonville')
round_robin('Denver', 'New England', 'Jacksonville', 'Green Bay', 'San Diego')

-- Denver vs. New England
-- 1 games

-- Denver vs. New England
-- Denver vs. Jacksonville
-- New England vs. Jacksonville
-- 3 games

-- Denver vs. New England
-- Denver vs. Jacksonville
-- Denver vs. Green Bay
-- Denver vs. San Diego
-- New England vs. Jacksonville
-- New England vs. Green Bay
-- New England vs. San Diego
-- Jacksonville vs. Green Bay
-- Jacksonville vs. San Diego
-- Green Bay vs. San Diego
-- 10 games