Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Python Solution:</p> <pre><code>import itertools def subsets(items, count = None): if count is None: count = len(items) for idx in range(count + 1): for group in itertools.combinations(items, idx): yield frozenset(group) def to_players(games): return [game[0] for game in games] + [game[1] for game in games] def rounds(games, court_count): for round in subsets(games, court_count): players = to_players(round) if len(set(players)) == len(players): yield round def is_canonical(player_count, games_played): played = [0] * player_count for players in games_played: for player in players: played[player] += 1 return sorted(played) == played def solve(court_count, player_count): courts = range(court_count) players = range(player_count) games = list( itertools.combinations(players, 2) ) possible_rounds = list( rounds(games, court_count) ) rounds_last = {} rounds_all = {} choices_last = {} choices_all = {} def update(target, choices, name, value, choice): try: current = target[name] except KeyError: target[name] = value choices[name] = choice else: if current &gt; value: target[name] = value choices[name] = choice def solution(games_played, players, score, choice, last_players): games_played = frozenset(games_played) players = frozenset(players) choice = (choice, last_players) update(rounds_last.setdefault(games_played, {}), choices_last.setdefault(games_played, {}), players, score, choice) update(rounds_all, choices_all, games_played, score, choice) solution( [], [], 0, None, None) for games_played in subsets(games): if is_canonical(player_count, games_played): try: best = rounds_all[games_played] except KeyError: pass else: for next_round in possible_rounds: next_games_played = games_played.union(next_round) solution( next_games_played, to_players(next_round), best + 2, next_round, []) for last_players, score in rounds_last[games_played].items(): for next_round in possible_rounds: if not last_players.intersection( to_players(next_round) ): next_games_played = games_played.union(next_round) solution( next_games_played, to_players(next_round), score + 1, next_round, last_players) all_games = frozenset(games) print rounds_all[ all_games ] round, prev = choices_all[ frozenset(games) ] while all_games: print "X ", list(round) all_games = all_games - round if not all_games: break round, prev = choices_last[all_games][ frozenset(prev) ] solve(2, 6) </code></pre> <p>Output:</p> <pre><code>11 X [(1, 2), (0, 3)] X [(4, 5)] X [(1, 3), (0, 2)] X [] X [(0, 5), (1, 4)] X [(2, 3)] X [(1, 5), (0, 4)] X [] X [(2, 5), (3, 4)] X [(0, 1)] X [(2, 4), (3, 5)] </code></pre> <p>This means it will take 11 rounds. The list shows the games to be played in the rounds in reverse order. (Although I think the same schedule works forwards and backwords.) I'll come back and explain why I have the chance.</p> <p><em><strong>Gets incorrect answers for one court, five players.</em></strong></p>
    singulars
    1. This table or related slice is empty.
    1. POTennis match scheduling
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USWinston Ewert
    1. USWinston Ewert
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CORunning this, I get the output "11". and that's it. I don't know why. The value of games, at the end, is [(0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5), (3, 4), (3, 5), (4, 5)], but the print rounds_all[ ] fails.
      singulars
      1. PO
      1. USWarren P
    2. CO@Warren P, The 11 should be the minimum number of rounds required. (Is it correct?) It doesn't give the actual games played. I can add that but I didn't. games is a list of all the games that have to be played.
      singulars
      1. PO
      1. USWinston Ewert
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload