Java足球联赛赛程生成算法问题：洗牌偶致程序卡顿

需求说明 #

需要实现足球联赛赛程生成功能，具体要求：

• 赛季上半程生成各周对阵，示例格式如下：

Half round of the season
1. week
Team1 - Team2
Team3 - Team4
2. week
Team1 - Team3
Team2 - Team4
3. week
Team1 - Team4
Team2- Team3
...

• 赛季下半程对阵主客场完全互换，计划通过homeT和awayT两个LinkedList实现

问题现象 #

当前上半程生成逻辑存在问题：使用Collections.shuffle()方法打乱球队列表时，程序有时能成功生成所有周的赛程，有时会卡顿无法完成全部计算。

实现逻辑 #

1. 从控制台获取球队数量，依次输入球队名称并存入LinkedList
2. 先生成第一周的赛程，再通过条件判断生成后续周的赛程
3. 怀疑问题出在检查对阵是否重复的for循环，该循环有时能正确执行，有时无法正常工作

完整代码 #

public void run() {
    System.out.print("Enter team count: ");
    Scanner scanner = new Scanner(System.in);
    int teamCount = scanner.nextInt();
    LinkedList<String> teams = new LinkedList<>();
    for (int i = 0; i < teamCount; i++) {
        System.out.print("Enter team name: ");
        teams.add(scanner.next());
    }

    for (String i : teams) {
        System.out.print(i + " ");
    }
    LinkedList<String> homeT = new LinkedList<>();
    LinkedList<String> awayT = new LinkedList<>();
    LinkedList<String> cloneList = new LinkedList<>();
    int counter = 1;
    boolean afterFirstWeek = false;
    boolean t = false;
    for (int i = 0; i < teamCount - 1; i++) {
        String homeTeam;
        String awayTeam;
        int matchCount = 0;
        String weeksMatches = "";

        cloneList = (LinkedList<String>) teams.clone(); // 每周刷新球队列表

        while (matchCount < teamCount / 2) {
            boolean isContinue = true;
            if (afterFirstWeek) {
                Collections.shuffle(cloneList);
                homeTeam = cloneList.peek();
                cloneList.removeFirst();
                awayTeam = cloneList.peek();
                cloneList.removeFirst();

                for (int j = 0; j < homeT.size(); j++) {
                    if ((homeTeam.equals(homeT.get(j)) && awayTeam.equals(awayT.get(j))) || (awayTeam.equals(awayT.get(j)) && homeTeam.equals(homeT.get(j)))) {
                        isContinue = false;
                    }
                    if (homeTeam.equals(awayT.get(j)) && awayTeam.equals(homeT.get(j))) {
                        isContinue = false;
                    }
                }

                if (isContinue) {
                    homeT.add(homeTeam);
                    awayT.add(awayTeam);
                    weeksMatches += homeTeam + " vs " + awayTeam + "\n";
                    matchCount++;
                    counter++;
                } else {
                    Collections.shuffle(cloneList);
                    cloneList.add(homeTeam);
                    cloneList.add(awayTeam);
                    Collections.shuffle(cloneList);
                }
            } else {
                Collections.shuffle(cloneList);
                homeTeam = cloneList.peek();
                cloneList.removeFirst();
                awayTeam = cloneList.peek();
                cloneList.removeFirst();

                homeT.add(homeTeam);
                awayT.add(awayTeam);
                weeksMatches += homeTeam + " vs " + awayTeam + "\n";
                matchCount++;
                counter++;

            }
            if (!afterFirstWeek && matchCount == teamCount / 2)
                afterFirstWeek = true;
        }
        System.out.println();
        System.out.println(i + 1 + ". week matches");
        System.out.println(weeksMatches);
    }

    for (int i = 0; i < counter; i++) {

    }
}

疑似问题代码片段 #

for (int j = 0; j < homeT.size(); j++) {
    if ((homeTeam.equals(homeT.get(j)) && awayTeam.equals(awayT.get(j))) || (awayTeam.equals(awayT.get(j)) && homeTeam.equals(homeT.get(j)))) {
        isContinue = false;
    }
    if (homeTeam.equals(awayT.get(j)) && awayTeam.equals(homeT.get(j))) {
        isContinue = false;
    }
}

内容的提问来源于stack exchange，提问作者Akın