Bird
Raised Fist0

What is the time complexity of the optimal recursive approach to invert a binary tree with n nodes?

medium🪤 Complexity Trap Q5 of Q15
Tree: Depth-First Search - Invert Binary Tree
What is the time complexity of the optimal recursive approach to invert a binary tree with n nodes?
AO(n^2)
BO(n log n)
CO(n)
DO(log n)
Step-by-Step Solution
Solution:

  1. Step 1: Analyze traversal

    The algorithm visits each node exactly once to swap children.

  2. Step 2: Confirm linear time

    Since each node is processed once, total time is proportional to n.

  3. Final Answer:

    Option C -> Option C

  4. Quick Check:

    One visit per node -> O(n) time [OK]
Quick Trick: One pass over all nodes -> O(n) [OK]
Common Mistakes:
MISTAKES
  • Assuming O(n log n) due to recursion
  • Confusing with sorting complexities
Trap Explanation:
PITFALL
  • Candidates often overestimate complexity due to recursion overhead, picking O(n log n).
Interviewer Note:
CONTEXT
  • Tests understanding of recursion and traversal complexity
Master "Invert Binary Tree" in Tree: Depth-First Search

3 interactive learning modes - each teaches the same concept differently

Try ItSolutionTrace

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions
More Tree: Depth-First Search Quizzes
Binary Tree Postorder Traversal - Binary Tree Postorder Traversal - Quiz 2easy Binary Tree Preorder Traversal - Binary Tree Preorder Traversal - Quiz 1easy Binary Tree Preorder Traversal - Binary Tree Preorder Traversal - Quiz 7medium Diameter of Binary Tree - Diameter of Binary Tree - Quiz 2easy Diameter of Binary Tree - Diameter of Binary Tree - Quiz 8hard House Robber III (On Tree) - House Robber III (On Tree) - Quiz 7medium Lowest Common Ancestor of Binary Tree - Lowest Common Ancestor of Binary Tree - Quiz 11easy Lowest Common Ancestor of Binary Tree - Lowest Common Ancestor of Binary Tree - Quiz 5medium Serialize and Deserialize Binary Tree - Serialize and Deserialize Binary Tree - Quiz 8hard Symmetric Tree (DFS Approach) - Symmetric Tree (DFS Approach) - Quiz 4medium