0110.Balanced Binary Tree

Link: 110. Balanced Binary Tree
Track: Amazon Tag

Question

Restate

Edge Case

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Method 1
Method 2

Method

Approach

(discussed at lease two approach?)

Complexity

• Time Complexity: O(n)
• Space Complexity: O(h)

Code

class Solution:
    def isBalanced(self, root: Optional[TreeNode]) -> bool:
        
        def helper(node):
            if not node:
                return 0
            
            left = helper(node.left)
            right = helper(node.right)
            
            if left == -1:
                return -1
            
            if right == -1:
                return -1
            
            if abs(left - right) > 1:
                return -1
            
            return max(left, right) + 1
            
        return False if helper(root) == -1 else True

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History

• Feb-27-2026 Hinted