Find kth largest element in binary tree
Last updated: September 1, 2025
Quick Overview
Given a binary tree, write a function to find the kth largest element in the tree. The function should take the root of the binary tree and an integer k as inputs, and return the kth largest element as an integer. You may assume that k is always valid, and there are no duplicate elements in the tree.
Zscaler
September 1, 20259
8
1,155 solved
Given a binary tree, write a function to find the kth largest element in the tree. The function should take the root of the binary tree and an integer k as inputs, and return the kth largest element as an integer. You may assume that k is always valid, and there are no duplicate elements in the tree.
Coding interviews at Zscaler focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
What the Interviewer Expects
- Recognize the underlying problem pattern (sliding window, two pointers, BFS/DFS, etc.)
- Discuss multiple approaches and trade-offs before coding
- Implement an optimal solution with clean, production-quality code
- Handle all edge cases including boundary conditions and invalid input
- Optimize both time and space complexity with clear justification
- Test your solution systematically with well-chosen examples
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
- Can you optimize the space complexity of your solution?
- How would you parallelize this solution?
- Can you solve this iteratively instead of recursively (or vice versa)?
- What is the worst-case input for your solution?
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 kth largest element in a binary tree, we can utilize the properties of a binary search tree (BST). However, since the problem doesn't guarantee the tree is a BST, we will explore using a d...
Approach
- Traversal: We will perform a reverse in-order traversal (right -> root -> left) since we want the largest elements first.
- Counting: As we traverse, we will maintain a counter to track ho...
Submit Your Answer
