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A complete binary tree is a binary tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possible.

Write a data structure CBTInserter that is initialized with a complete binary tree and supports the following operations:

  • CBTInserter(TreeNode root) initializes the data structure on a given tree with head node root;
  • CBTInserter.insert(int v) will insert a TreeNode into the tree with value node.val = v so that the tree remains complete, and returns the value of the parent of the inserted TreeNode;
  • CBTInserter.get_root() will return the head node of the tree.

 

Example 1:

Input: inputs = ["CBTInserter","insert","get_root"], inputs = [[[1]],[2],[]]
Output: [null,1,[1,2]]

Example 2:

Input: inputs = ["CBTInserter","insert","insert","get_root"], inputs = [[[1,2,3,4,5,6]],[7],[8],[]]
Output: [null,3,4,[1,2,3,4,5,6,7,8]]

 

Note:

  1. The initial given tree is complete and contains between 1 and 1000 nodes.
  2. CBTInserter.insert is called at most 10000 times per test case.
  3. Every value of a given or inserted node is between 0 and 5000.

 

 

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * TreeNode(int val) { this.val = val; } * TreeNode(int val, TreeNode left, TreeNode right) { * this.val = val; * this.left = left; * this.right = right; * } * } */ class CBTInserter { public CBTInserter(TreeNode root) { } public int insert(int v) { } public TreeNode get_root() { } } /** * Your CBTInserter object will be instantiated and called as such: * CBTInserter obj = new CBTInserter(root); * int param_1 = obj.insert(v); * TreeNode param_2 = obj.get_root(); */