Find kth largest element in binary tree
Last updated: April 12, 2026
Quick Overview
Given a binary tree, write a function to find the k-th largest element in the tree. You may assume that k is always valid, and the tree contains at least k nodes. The function should return the k-th largest value as an integer.
Anthropic
April 12, 2026100
15
2,288 solved
Given a binary tree, write a function to find the k-th largest element in the tree. You may assume that k is always valid, and the tree contains at least k nodes. The function should return the k-th largest value as an integer.
This coding problem is frequently asked during Take-home Project at Anthropic. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Anthropic expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- What if the input doesn't fit in memory?
- How would you modify your solution to handle streaming input?
- Can you solve this iteratively instead of recursively (or vice versa)?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice DSA ProblemsSample Answer
Problem Analysis
To find the k-th largest element in a binary tree, we can leverage the properties of in-order traversal. In a binary search tree (BST), an in-order traversal yields elements in sorted order. However, ...
Approach
- Initialize a counter to keep track of how many nodes we have visited.
- Define a recursive function that performs a DFS on the binary tree.
- Visit the right child first (as larger values are o...
Submit Your Answer
Anthropic Machine Learning Engineer Interview Guide
Interview process, tips, and preparation timeline