654. Maximum Binary Tree¶

Edited by Charles

Medium · Python · Binary Tree

Problem

The official page contains the problem statement, examples, and constraints.

Explanation, examples & other approaches

Core idea

Recursion:

See 106. Construct Binary Tree from Inorder and Postorder Traversal and 105. Construct Binary Tree from Preorder and Inorder Traversal for the core idea of recursion.

Original study notes follow, including intermediate snippets and earlier attempts.

Recursion:

See 106. Construct Binary Tree from Inorder and Postorder Traversal and 105. Construct Binary Tree from Preorder and Inorder Traversal for the core idea of recursion.

Study record

Field	Value
Attempts	1
Mastery	❚
The Latest Attempt	January 15, 2026

Python solution¶

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def constructMaximumBinaryTree(self, nums: List[int]) -> Optional[TreeNode]:
        if not nums:
            return None

        rootVal = max(nums)
        idx = nums.index(rootVal)

        root = TreeNode(rootVal)
        root.left = self.constructMaximumBinaryTree(nums[: idx])
        root.right = self.constructMaximumBinaryTree(nums[idx + 1:])

        return root

Back to Day 15 Binary Tree V · All Algorithm notes