"""

 Given a binary tree with the following rules:

     root.val == 0

     If treeNode.val == x and treeNode.left != null, then treeNode.left.val == 2 * x + 1

     If treeNode.val == x and treeNode.right != null, then treeNode.right.val == 2 * x + 2

 Now the binary tree is contaminated, which means all treeNode.val have been changed to -1.

 You need to first recover the binary tree and then implement the FindElements class:

     FindElements(TreeNode* root) Initializes the object with a contamined binary tree, you need to recover it first.

     bool find(int target) Return if the target value exists in the recovered binary tree.

 Example 1:

 Input

 ["FindElements","find","find"]

 [[[-1,null,-1]],[1],[2]]

 Output

 [null,false,true]

 Explanation

 FindElements findElements = new FindElements([-1,null,-1]);

 findElements.find(1); // return False

 findElements.find(2); // return True

 Example 2:

 Input

 ["FindElements","find","find","find"]

 [[[-1,-1,-1,-1,-1]],[1],[3],[5]]

 Output

 [null,true,true,false]

 Explanation

 FindElements findElements = new FindElements([-1,-1,-1,-1,-1]);

 findElements.find(1); // return True

 findElements.find(3); // return True

 findElements.find(5); // return False

 Example 3:

 Input

 ["FindElements","find","find","find","find"]

 [[[-1,null,-1,-1,null,-1]],[2],[3],[4],[5]]

 Output

 [null,true,false,false,true]

 Explanation

 FindElements findElements = new FindElements([-1,null,-1,-1,null,-1]);

 findElements.find(2); // return True

 findElements.find(3); // return False

 findElements.find(4); // return False

 findElements.find(5); // return True

 """

 class TreeNode:

     def __init__(self, x):

         self.val = x

         self.left = None

         self.right = None

 class FindElements:

     def __init__(self, root):

         self.array = []  # !!!保存结点出现的值,注意self. 私有成员

         if root != None:  # 调用递归函数

             self.recover_tree(root, 0)

     def recover_tree(self, root, v):  # 递归调用

         root.val = v

         self.array.append(v)

         if root.left != None:

             self.recover_tree(root.left, 2 * v + 1)

         if root.right != None:

             self.recover_tree(root.right, 2 * v + 2)

     def find(self, target: int) -> bool:

         return target in self.array  # 再结果数组里找