Maximum Binary Tree II

We are given the root node of a maximum tree: a tree where every node has a value greater than any other value in its subtree.

Just as in the previous problem, the given tree was constructed from an list A (root = Construct(A)) recursively with the following Construct(A) routine:

  • If A is empty, return null.

  • Otherwise, let A[i] be the largest element of A. Create a root node with value A[i].

  • The left child of root will be Construct([A[0], A[1], ..., A[i-1]])

  • The right child of root will be Construct([A[i+1], A[i+2], ..., A[A.length - 1]])

  • Return root.

Note that we were not given A directly, only a root node root = Construct(A).

Suppose B is a copy of A with the value val appended to it. It is guaranteed that B has unique values.

Return Construct(B).

Example 1:

Input: root = [4,1,3,null,null,2], val = 5
Output: [5,4,null,1,3,null,null,2]
Explanation: A = [1,4,2,3], B = [1,4,2,3,5]

Example 2:

Input: root = [5,2,4,null,1], val = 3
Output: [5,2,4,null,1,null,3]
Explanation: A = [2,1,5,4], B = [2,1,5,4,3]

Example 3:

Input: root = [5,2,3,null,1], val = 4
Output: [5,2,4,null,1,3]
Explanation: A = [2,1,5,3], B = [2,1,5,3,4]

Constraints:

  • 1 <= B.length <= 100

class Solution {
    public TreeNode insertIntoMaxTree(TreeNode root, int val) {
        // Value is appended to the end of the array from which 'A' was constructed
        // Refer "Maximum Binary Tree" for understanding completely
        if (root == null) {
            TreeNode node = new TreeNode(val);
            return node;
        }
        if (root.val < val) {
            TreeNode node = new TreeNode(val);
            node.left = root;
            return node;
        }
        root.right = insertIntoMaxTree(root.right, val);
        return root;
    }
}

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