Java 代码

public class Main{
    public static void main(String[] args){
        LinkedList<Character> a = new LinkedList<>();
        LinkedList<Character> b = new LinkedList<>();
        LinkedList<Character> c = new LinkedList<>();
        //出牌顺序,A为true,B为false
        boolean flag = true;
        start(a, b);

        //保存源牌组的字符串序列
        String srcA = replaceToString(a);
        String srcB = replaceToString(b);

        while (!a.isEmpty() && !b.isEmpty()) {
            LinkedList<Character> tem = new LinkedList<>();
            //a出牌
            if (flag) {
                char target = a.removeFirst();
                c.add(target);
                tem = get(c, target);
                a.addAll(tem);
            } else {//b出牌
                char target = b.removeFirst();
                c.add(target);
                tem = get(c, target);
                b.addAll(tem);
            }
            //获取当前牌组字符串序列
            String temA = replaceToString(a);
            String temB = replaceToString(b);

            //判断当前字符串是否与源字符串相同,若相同则说明本局永远不会结束,输出-1结束程序
            if (srcA.contentEquals(temA) && srcB.contentEquals(temB)) {
                System.out.println(-1);
                System.exit(0);
            }
            //本局没有赢家,换人出牌
            if (tem.isEmpty()) {
                flag = !flag;
            }

        }

        //输出不为空的牌组
        if (b.isEmpty()) {
            System.out.println(replaceToString(a));
        } else {
            System.out.println(replaceToString(b));
        }


    }
    //获取牌相同之间的牌
    private static LinkedList<Character> get(LinkedList<Character> c, char target) {
        LinkedList<Character> tem = new LinkedList<>();
        int index = c.indexOf(target);
        int n = c.size();
        if (index >= 0 && index != n-1) {
            for (int i = 0; i < n - index; i++) {
                tem.add(c.removeLast());
            }
        }
        return tem;
    }

    //将字符集合转化为字符串
    public static String replaceToString(LinkedList<Character> target) {
        StringBuilder sb = new StringBuilder();
        for (Character character : target) {
            sb.append(character);
        }
        return sb.toString();
    }

    //初始化
    public static void start(LinkedList<Character> a, LinkedList<Character> b) {
        Scanner sc = new Scanner(System.in);
        char[] astr = sc.nextLine().toCharArray();
        char[] bstr = sc.nextLine().toCharArray();
        int n = astr.length;
        for (int i = 0; i < n; i++) {
            a.add(astr[i]);
            b.add(bstr[i]);
        }
    }
}