public class Test {

    int length;
    int[][] allPossible;
    String[][] allOperate;

    int[] current;
    String[] operate;

    int[] inOrder;
    int[] outOrder;

    List<Integer> list;//这个当做栈

    Test(int... ints) {//123321,后面3个是要求的出栈顺序，可以不用理会
        length = ints.length / 2;

        allPossible = new int[100][length];//不想分析有几种可能，暂定100行
        allOperate = new String[100][length * 2];

        current = new int[length];
        operate = new String[length * 2];

        inOrder = new int[length];
        for (int i = 0; i < length; i++) {
            inOrder[i] = ints[i];
        }

        outOrder = new int[length];
        for (int i = 0; i < length; i++) {
            outOrder[i] = ints[i + length];
        }

        list = new ArrayList<>();
    }

    void back(int level, int index, int operateIndex) {//1,2带进去验证 level = 0 length = 2//最后发现index还是有必要的
        if (level == length) {
            // TODO: 2017/11/19 这里执行的是：把当前记录的出栈情况数组添加到所有情况的二维数组里，最后一起输出
            int row = -1;
            //找到第一个没有被赋值过的行,这个找到的i就是pure(纯净，未赋值过的)行号
            for (int i = 0; i < 100; i++) {
                if (allPossible[i][length - 1] == 0) {
                    row = i;
                    break;
                }
            }
            //把栈中剩余的数按出栈顺序读到结果数组里，实际上不出栈,怕影响之前的情况
            for (int i = 0; i < list.size(); i ++) {//经检验，list出栈的数据完全正确！
                int num = list.get(i);
                for (int j = length - 1; j >= 0; j --) {
                    if (allPossible[row][j] == 0) {
                        allPossible[row][j] = num;
                        break;
                    }
                }
            }
            //把current里的结果也一并加上
            for (int i = 0; i < length; i++) {
                if (allPossible[row][i] == 0) {
                    allPossible[row][i] = current[i];
                } else break;
            }

            //operate进行最后处理，剩下没填满的位数，全部记成out
            for (int i = 0; i < length * 2; i ++) {
                if (operate[i] == null) {
                    operate[i] = "out";
                }
            }

            //把operate全部记到allOperate二维数组里
            for (int i = 0; i < length * 2; i ++) {
                allOperate[row][i] = operate[i];
            }
            return;
        } else {//这里level是0到最后一层，index指代当前操作数，如果仍在这个范围内，代表数没用完
            if (list.size() == 0) {
                list.add(inOrder[level]);

                operate[operateIndex] = "in";

                back(level + 1, index, operateIndex + 1);
                list.remove(list.size() - 1);
            } else {
                for (int i = 0; i < 2; i++) {
                    if (i == 0) {
                        list.add(inOrder[level]);

                        operate[operateIndex] = "in";

                        back(level + 1, index, operateIndex + 1);
                        list.remove(list.size() - 1);
                    } else {
                        int num = list.remove(list.size() - 1);
                        current[index] = num;

                        operate[operateIndex] = "out";

                        back(level, index + 1, operateIndex + 1);
                        list.add(num);
                    }
                }
            }
        }
    }

    void print() {
        int row = -1;
        for (int i = 0; i < 100; i++) {
            if (allPossible[i][0] == 0) {
                row = i;
                break;
            }
        }
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < length; j++) {
                System.out.print(allPossible[i][j] + " ");
            }
            System.out.println();
        }

        for (int i = 0; i < row; i++) {
            for (int j = 0; j < length * 2; j++) {
                System.out.print(allOperate[i][j] + " ");
            }
            System.out.println();
        }
    }

    public static void main(String[] args) throws Exception {
        Test test = new Test(1, 2, 3, 4, 4, 3, 2, 1);
        test.back(0, 0, 0);
        test.print();
    }
}