Merge K Sorted matrixs

Last updated: March 20, 2026

Quick Overview

Given two sorted binary trees, merge them into a single sorted result.

Zscaler
Coding & Algorithms
Software Engineer
Zscaler
March 20, 2026
Software Engineer
Technical Screen
Coding & Algorithms
Easy

15

13

2,714 solved


Given two sorted binary trees, merge them into a single sorted result.

Zscaler uses this problem in the Technical Screen 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
Tree structures and recursion
Hash maps and frequency counting
Edge cases and input validation
Common algorithm patterns (sliding window, two pointers, BFS/DFS)
How to Approach This
  1. Clarify input constraints and edge cases before writing code.
  2. Walk through your approach verbally and confirm with the interviewer before coding.
  3. Start with a brute force solution, then optimize. Mention time and space complexity.
  4. Test your solution with examples, including edge cases like empty input or duplicates.
  5. Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
  • Can you solve this iteratively instead of recursively (or vice versa)?
  • What happens if the input contains duplicates?
  • Can you solve this in a single pass?
  • How would you parallelize this solution?
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Sample Answer
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Brute Force Approach

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