110. Balanced Binary Tree

Edited by Charles

Easy · Python · Binary Tree

Problem

Read the original problem on LeetCode.

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

Explanation, examples & other approaches

Core idea

Recursion

Reference to 104. Maximum Depth of Binary Tree

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

Recursion

Reference to 104. Maximum Depth of Binary Tree

Study record

Field	Value
Attempts	1
Mastery	❚
The Latest Attempt	January 13, 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 __init__(self):
        self.checkBalanced = True

    def isBalanced(self, root: Optional[TreeNode])->bool:
        self.maxDepth(root)
        return self.checkBalanced

    def maxDepth(self, node):
        if not node:
            return 0

        leftHeight= self.maxDepth(node.left)
        rightHeight= self.maxDepth(node.right)

        if abs(leftHeight- rightHeight)>1:
            self.checkBalanced = False

        return 1 + max(leftHeight, rightHeight)

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