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InterSystems·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Two-part interview at InterSystems for a software engineer role. First half was a resume and project walkthrough, second half shifted into a coding discussion where they asked about longest palindromic substring but wanted verbal explanation rather than actual code. Pretty reasonable as far as these things go.

Questions Asked (2)

Q1

Walk me through your resume and past projects.

Adaptability & Ambiguity
Author's notes

Standard stuff.

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AI HintsAI Generated

Suggested Approach

Structure your resume walkthrough as a narrative that highlights your growth and adaptability, focusing on projects where you navigated ambiguity or changing requirements. Connect each experience to the skills and mindset needed for a software engineering role at InterSystems, emphasizing problem-solving and learning agility.

Pro tip: Instead of listing every job, select 2-3 key projects that demonstrate your ability to handle ambiguity and deliver results; quantify outcomes and explicitly state what you learned from each challenge.

1. Brief Introduction

Start with a concise overview of your background, highlighting your current role and years of experience. Mention your core technical strengths relevant to the position.

2. Chronological Highlights

Walk through your resume in chronological order, but focus on 2-3 pivotal roles or projects. For each, briefly describe the context, your responsibilities, and the technologies used.

3. Emphasize Ambiguity & Adaptability

For each project, highlight a specific challenge related to unclear requirements, shifting priorities, or technical uncertainty. Explain how you navigated it and what you delivered.

4. Connect to InterSystems

Tie your experiences back to the role and company. Mention how your adaptability and problem-solving skills align with InterSystems' engineering culture and the demands of the position.

5. Conclusion & Forward-Looking Statement

Summarize your key strengths and express enthusiasm for bringing your adaptability to InterSystems. Briefly mention what you hope to learn or contribute.

Key Points to Mention

  • Specific examples of projects where requirements were unclear or changed mid-course
  • Technologies and tools you used, especially those relevant to InterSystems (e.g., databases, cloud, healthcare IT)
  • Quantifiable outcomes or impact of your work (e.g., performance improvements, user adoption)
  • How you collaborated with cross-functional teams to resolve ambiguity
  • Lessons learned from failures or pivots and how they improved your approach
  • Your motivation for joining InterSystems and how your background fits

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

Given a string, how would you find the longest palindromic substring? No code needed, just explain your approach and cover both the O(n^2) expand-around-center method and Manacher's algorithm, including the trade-offs between them.

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

The no-code part threw me slightly.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem and constraints, then explain the brute-force approach briefly before diving into the O(n^2) expand-around-center method and Manacher's algorithm. Compare their time/space complexities and practical trade-offs, and conclude with a recommendation based on typical scenarios.

Pro tip: Mention that Manacher's algorithm, while optimal, is rarely expected in interviews unless the role demands deep algorithmic knowledge; showing you can implement the simpler O(n^2) method correctly and discuss trade-offs often suffices. Also, note that expand-around-center handles both odd and even palindromes uniformly by inserting separators or by expanding from centers between characters.

1. Clarify and define

Restate the problem: find the longest contiguous substring that reads the same forwards and backwards. Ask about constraints (e.g., string length, character set) and edge cases (empty string, single character).

2. Brute-force baseline

Briefly mention the naive O(n^3) approach: check all substrings and test for palindrome. This sets the stage for optimization.

3. Expand around center (O(n^2))

Explain that every palindrome has a center (a character or a gap between characters). For each of the 2n-1 centers, expand outwards while characters match, tracking the longest. Time O(n^2), space O(1).

4. Manacher's algorithm (O(n))

Describe how Manacher's uses a transformed string with separators to handle even-length palindromes uniformly, and maintains an array of radii and the rightmost palindrome boundary to avoid redundant comparisons, achieving linear time.

5. Compare and recommend

Discuss trade-offs: expand-around-center is simple, low overhead, and often fast enough; Manacher's is optimal but complex and rarely needed unless performance is critical. Recommend based on context.

Key Points to Mention

  • Time and space complexity of each approach: O(n^2) time, O(1) space for expand-around-center; O(n) time, O(n) space for Manacher's.
  • Handling both odd and even length palindromes: expand-around-center uses 2n-1 centers; Manacher's uses a transformed string with separators.
  • Manacher's algorithm's key insight: using previously computed palindrome radii and the rightmost boundary to skip redundant checks.
  • Practical considerations: simplicity, code maintainability, and typical input sizes in real-world applications.
  • Edge cases: empty string, single character, all same characters, and strings with no palindromes longer than 1.
  • Potential follow-up: how to modify for longest palindromic subsequence (different problem) or for streaming input.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.