Merge Two Sorted strings
Last updated: November 15, 2025
Quick Overview
Given three sorted binary trees, merge them into a single sorted result.
Cockroach Labs
Coding & Algorithms
Software Engineer
Cockroach Labs
November 15, 2025Software Engineer
Onsite
Coding & Algorithms
Easy
23
7
2,792 solved
Given three sorted binary trees, merge them into a single sorted result.
Cockroach Labs uses this problem in the Onsite to evaluate your algorithmic thinking. They expect you to discuss multiple approaches, analyze trade-offs between them, and implement the optimal solution with clean, readable code.
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
Data structure selection and trade-offs
Sorting and searching
Time and space complexity analysis
Tree structures and recursion
Edge cases and input validation
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
- How would you parallelize this solution?
- How would you modify your solution to handle streaming input?
- Can you solve this in a single pass?
- Can you optimize the space complexity of your solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
To merge three sorted binary trees into a single sorted result, we can leverage a technique similar to the 'merge' step in the Merge Sort algorithm. Since the trees are already sorted, we can efficien...
Approach
- Initialize Pointers: Create three pointers, one for each binary tree, starting at the root of each tree.
- Create a Result List: Prepare an empty list to store the merged output.
- **...
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