Merge Three Sorted strings
Last updated: March 16, 2026
Quick Overview
Given three sorted arrays, merge them into a single sorted result.
Postmates
Coding & Algorithms
Software Engineer
Postmates
March 16, 2026Software Engineer
Onsite
Coding & Algorithms
Medium
128
13
3,781 solved
Given three sorted arrays, merge them into a single sorted result.
Coding interviews at Postmates 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
Edge cases and input validation
Dynamic programming and memoization
Tree structures and recursion
Binary search and divide and conquer
Time and space complexity analysis
Sorting and searching
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 test this solution thoroughly?
- Can you optimize the space complexity of your solution?
- What is the worst-case input for your solution?
- What if the input doesn't fit in memory?
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Practice DSA ProblemsSample Answer
Problem Analysis
To solve the problem of merging three sorted strings, we can recognize that this is a classic merging problem similar to merging two sorted arrays. The best approach here is to utilize the **two point...
Approach
- Initialize Pointers: Create three pointers, one for each string, initialized to zero. This will help us track our current position in each string.
- Create Result List: Initialize an empty...
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