AndroidTraining-ahut2020

    /**
     * 随机搜索器的实现v1.0
     * 枚举运算符的种类,构造出后缀表达式
     * @param arr
     * @return
     */
    public static List<String> search(int[] arr) {
        for (int x = 0; x < 4; x++)
            for (int y = 0; y < 4; y++)
                for (int z = 0; z < 4; z++) {
                    List<String> exp = new Vector<>();
                    exp.add(OPERATORS[x]);
                    exp.add(OPERATORS[y]);
                    exp.add(OPERATORS[z]);
                    for (int i : arr) exp.add(Integer.toString(i));
                    for (int i = 0; i < MAX_COUNT; i++) {
                        Collections.shuffle(exp);
                        double val = PostExpression.eval(exp);
                        if (val == 24.0) {
                            return exp;
                        }
                    }
                }
        return null;
    }

/**
     * 根据后缀表达式生成运算二叉树
     * @param exp
     * @return
     */
static BinaryTree createBinaryTree(List<String> exp) {
    Stack<BinaryTree> S = new Stack<>();
    for (String tok : exp) {
        if (PostExpression.isNumber(tok)) {
            BinaryTree tree = new BinaryTree(tok);
            S.push(tree);
        } else {
            BinaryTree right = S.peek();
            S.pop();
            BinaryTree left = S.peek();
            S.pop();
            BinaryTree tree = new BinaryTree(tok, left, right);
            S.push(tree);
        }
    }
    return S.peek();
}

void midVisit() {//中序左子树，中序右子树 根节点
    System.out.print("(");
    if (left != null) {
        left.midVisit();
    }
    System.out.print(root);
    if (right != null) {
        right.midVisit();
    }
    System.out.print(")");
}

public class SubSetDFS {//递归程序
    static int n = 5;
    static int[] book = new int[n];

    static void dfs(int k) {
        if (k >= n) {
            System.out.println(Arrays.toString(book));
            return;
        }
        book[k] = 0;
        dfs(k + 1);
        book[k] = 1;
        dfs(k + 1);
    }

    public static void main(String[] args) {
        dfs(0);
    }
}

public class Permutation2DFS { //递归程序
    static int n = 4;
    static int[] book = new int[n];
    static int[] arr = new int[n];

    static void dfs(int k) {
        if (k >= n) {
            System.out.println(Arrays.toString(arr));
            return;
        }
        for (int i = 0; i < n; i++) {
            if (book[i] == 1) continue;
            arr[k] = i;

            book[i] = 1;
            dfs(k + 1);
            book[i] = 0;
        }
    }

    public static void main(String[] args) {
        dfs(0);
    }
}

static final int FAC[] = { 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880 };
public static int[] codel(int x, int m) {
    int[] label = new int[m];
    int[] n = new int[m];
    int cnt;
    for (int i = 0; i < m; i++)
        label[i] = 1;
    for (int i = 0; i < m; i++) {
        cnt = x / FAC[m - 1 - i];
        x = x % FAC[m - 1 - i];
        for (int j = 0; j < m; j++) {
            if (label[j] == 0)
                continue;
            if (cnt == 0) {
                label[j] = 0;
                n[i] = j;
                break;
            }
            cnt--;
        }
    }
    return n;
}

public List<String> search(int[] arr) {
        //4！*4^3*5=24*64*5=7680 <<7!*64=32w+
        for (int cc = 0; cc < FAC[4]; cc++) {
            int[] idx = codel(cc, 4);
            String a = String.valueOf(arr[idx[0]]);
            String b = String.valueOf(arr[idx[1]]);
            String c = String.valueOf(arr[idx[2]]);
            String d = String.valueOf(arr[idx[3]]);
            for (int i = 0; i < 4; i++)
                for (int j = 0; j < 4; j++)
                    for (int k = 0; k < 4; k++) {
                        String X = OPERATORS[i];
                        String Y = OPERATORS[j];
                        String Z = OPERATORS[k];
                        for (String[] ee : new String[][]{
                                {a, b, X, c, Y, d, Z},
                                {a, b, c, X, Y, d, Z},
                                {a, b, X, c, d, Y, Z},
                                {a, b, c, X, d, Y, Z},
                                {a, b, c, d, X, Y, Z},}) {
                            if (Math.abs(PostExpression.eval(ee) - TARGET) < EPS) {
                                return Arrays.asList(ee);
                            }
                        }
                    }
        }
        return null;
    }

 public Set<List<String>> searchAll(int[] arr) {
        Set<List<String>> lists = new HashSet<List<String>>();
        for (int cc = 0; cc < FAC[4]; cc++) {
            int[] idx = codel(cc, 4);
            String a = String.valueOf(arr[idx[0]]);
            String b = String.valueOf(arr[idx[1]]);
            String c = String.valueOf(arr[idx[2]]);
            String d = String.valueOf(arr[idx[3]]);
            for (int i = 0; i < 4; i++)
                for (int j = 0; j < 4; j++)
                    for (int k = 0; k < 4; k++) {
                        String X = OPERATORS[i];
                        String Y = OPERATORS[j];
                        String Z = OPERATORS[k];
                        for (String[] ee : new String[][]{
                                {a, b, X, c, Y, d, Z},
                                {a, b, c, X, Y, d, Z},
                                {a, b, X, c, d, Y, Z},
                                {a, b, c, X, d, Y, Z},
                                {a, b, c, d, X, Y, Z},}) {
                            if (Math.abs(PostExpression.eval(ee) - TARGET) < EPS) {
                                lists.add(new Vector(Arrays.asList(ee)));
                            }
                        }
                    }
        }
        return lists;
    }

@Override
protected void onStop() {
    super.onStop();
    //缓存计算结果 shared-preference
    Log.i("point24", "saving preference!!!");
    SharedPreferences share = MainActivityProject.this.getSharedPreferences(FILENAME, Activity.MODE_PRIVATE);
    SharedPreferences.Editor edit = share.edit();
    edit.putString("a", editTextA.getText().toString());
    edit.putString("b", editTextB.getText().toString());
    edit.putString("c", editTextC.getText().toString());
    edit.putString("d", editTextD.getText().toString());
    edit.putString("sol", textViewSolution.getText().toString());
    edit.commit();// 提交更新
}

//读取shared-preference
Log.i("point24", "reading preference!!!");
SharedPreferences share = super.getSharedPreferences(FILENAME, Activity.MODE_PRIVATE);
editTextA.setText(share.getString("a", "0"));
editTextB.setText(share.getString("b", "0"));
editTextC.setText(share.getString("c", "0"));
editTextD.setText(share.getString("d", "0"));
textViewSolution.setText(share.getString("sol", "计算Ing,请等待"));

public class DatabaseHelper extends SQLiteOpenHelper{
    //带全部参数的构造函数，此构造函数必不可少
    public DatabaseHelper(Context context, String name, CursorFactory factory, int version) {
        super(context, name, factory, version);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        //创建数据库sql语句并执行
        String sql = "create table tb2(numbers varchar(20),solution varchar(50))";
        Log.i("DB","数据表创建成功");
        db.execSQL(sql);
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {    }
}

DatabaseHelper dbHelper = new DatabaseHelper(MainActivity.this,                        "test_db", null, 1);
Log.i("DB", "数据库创建成功");
final SQLiteDatabase db = dbHelper.getWritableDatabase();

int[] arr = new int[] { a, b, c, d };
Arrays.sort(arr);
String keys = Arrays.toString(arr);
// 先查询数据库的结果 如果存在直接读取结果
Log.i("DB", "start querying1!");
Cursor cursor = db.query("tb2", new String[] { "numbers","solution" }, null, null, null, null, null);
boolean find = false;
Log.i("DB", "start querying2!");
while (cursor.moveToNext()) {
    String numbers = cursor.getString(cursor.getColumnIndex("numbers"));
    if (numbers.equals(keys)) {
        String solution = cursor.getString(cursor.getColumnIndex("solution"));
        textViewResult.setText(solution);
        Toast.makeText(MainActivity.this,"读取本地数据库记录",Toast.LENGTH_SHORT).show();
        Log.i("DB", "query succesfully!");
        find = true;
        break;
    }
}
// 否则计算后存入数据库
if (!find) {
    String answer = Point24.solve(arr);
    textViewResult.setText(answer);			
    ContentValues values = new ContentValues();
    Log.i("DB", "start inserting!");
    values.put("numbers", keys);
    values.put("solution", answer);
    // 数据库执行插入命令
    db.insert("tb2", null, values);
    Log.i("DB", "insert succesfully!");
    Toast.makeText(MainActivity.this,"插入数据库成功",Toast.LENGTH_SHORT).show();
}