java足球比赛调度算法

Question

我将创建一个足球比赛调度算法。主要的日程安排规则（据我所知）是：

1. 球队的数量是偶数
2. 一个赛季包括两轮
3. 在一个比赛日内，每个队只打一场比赛
4. 上一个比赛日的主队应该是下一个比赛日的客队（如果可能的话——我看了意甲比赛，这条规则有一个例外——每支球队在一个赛季中连续打2次（主队/客队-第一轮/复仇轮）
5. 共有两轮，规则如下：第一轮（比赛日1）的第一场比赛A队与B队（A:B）比赛，因此复仇赛B:A应在-matchdayallMatchDays/2 + i进行，其中i = 1

目前的做法：

---

  private static Map<Integer, List<Match>> createSchedule(/*Set<Team> allTeams*/) {

    Set <Team> allTeams = Set.of(

            Team.builder().name("A").build(),
            Team.builder().name("B").build(),
            Team.builder().name("C").build(),
            Team.builder().name("D").build(),
            Team.builder().name("E").build(),
            Team.builder().name("F").build(),
            Team.builder().name("G").build(),
            Team.builder().name("H").build(),
            Team.builder().name("I").build(),
            Team.builder().name("J").build()

    );

    int teamsNumber = allTeams.size();
    int matchDays = (teamsNumber - 1) * 2;
    int gamesNumberPerMatchDay = teamsNumber / 2;

    List<Match> allMatches = allTeams.stream()
            .map(team ->
                    allTeams.stream().filter(otherTeam -> !otherTeam.equals(team))
                            .map(otherTeam -> Match.builder().homeTeam(team)
                                    .awayTeam(otherTeam).build()).collect(Collectors.toList())
            )
            .flatMap(Collection::stream)
            .collect(Collectors.toList());

    Map<Integer, List<Match>> schedule = IntStream.rangeClosed(1, matchDays)
            .boxed()
            .collect(Collectors.toMap(
                    matchDay -> (Integer) matchDay,
                    matchDay -> new ArrayList<>()));

    Set<Team> homeTeamsInCurrentMatchDay = new HashSet<>();
    List<Team> teamsScheduledForCurrentMatchDay = new ArrayList<>();

    /*matchDay*/
    for (int i = 1; i <= matchDays / 2; i++) {

        List<Team> homeTeamsInPreviousMatchDay = new ArrayList<>(homeTeamsInCurrentMatchDay);
        homeTeamsInCurrentMatchDay.clear();

        /*match number in current Matchday*/
        for (int j = 1; j <= gamesNumberPerMatchDay; j++) {

            /*first match*/

            Match match = drawMatch(allMatches, teamsScheduledForCurrentMatchDay, homeTeamsInPreviousMatchDay);

            allMatches.remove(match);

            schedule.get(i).add(match);

            homeTeamsInCurrentMatchDay.add(match.getHomeTeam());

            teamsScheduledForCurrentMatchDay.add(match.getHomeTeam());
            teamsScheduledForCurrentMatchDay.add(match.getAwayTeam());

            /*revenge match*/

            Match revengeMatch = Match.builder().homeTeam(match.getAwayTeam()).awayTeam(match.getHomeTeam()).build();

            schedule.get((matchDays / 2) + i).add(revengeMatch);

            allMatches.remove(revengeMatch);

        }
        teamsScheduledForCurrentMatchDay.clear();
    }

    return schedule;
}

private static Match drawMatch(List<Match> matches, List<Team> alreadyScheduledTeamsInCurrentMatchDay, List<Team> homeTeamsInPreviousMatchDay) {


    List<Match> possibleMatches = matches.stream()
            .filter(match -> !alreadyScheduledTeamsInCurrentMatchDay.contains(match.getHomeTeam()) && !alreadyScheduledTeamsInCurrentMatchDay.contains(match.getAwayTeam()))
            .collect(Collectors.toList());

    List<Match> possibleMatchesWithExclusionOfHomeTeams = new ArrayList<>(possibleMatches);

    possibleMatchesWithExclusionOfHomeTeams.removeIf(match -> homeTeamsInPreviousMatchDay.contains(match.getHomeTeam()));

    if (possibleMatchesWithExclusionOfHomeTeams.size() != 0) {
        possibleMatches = new ArrayList<>(possibleMatchesWithExclusionOfHomeTeams);
    }

    int randomNumber = new Random().nextInt(possibleMatches.size());
    return possibleMatches.get(randomNumber);
}

球队和比赛蓝图如下：

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
class Team {
    String name;
}


@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
class Match {

    private Team homeTeam;
    private Team awayTeam;
}

算法不起作用。

Exception in thread "main" java.lang.IllegalArgumentException: bound must be positive

抛出-这意味着对于某些球队的某个比赛日，有0个可能的比赛，这些比赛满足开头列出的规则。我不确定，我在这里遗漏了什么，以及调度算法应该如何反映真实的算法。换句话说，为什么possibleMatches.size()恰好是0以及应该做什么修正以使该算法正常工作