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DocuSign·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Interviewed for a SWE role at DocuSign and got a pretty straightforward array manipulation question. Nothing wild, but it's the kind of thing that trips you up if you're not careful about edge cases.

Questions Asked (1)

Q1

Given an array, implement add, remove, and update operations and return the modified array after each operation.

Algorithms & Data Structures
Author's notes

Seemed easy at first and I jumped straight into coding without clarifying the expected return behavior.

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AI HintsAI Generated

Suggested Approach

Clarify the requirements first: whether the array is static or dynamic, the expected time complexity for each operation, and whether operations are in-place or return a new array. Then choose an appropriate data structure (e.g., dynamic array for O(1) add/update and O(n) remove, or a balanced BST for O(log n) operations) and implement the operations with careful handling of edge cases like invalid indices.

Pro tip: Discuss the trade-offs between different data structures and mention that in a real-world scenario, you would consider using a library or built-in methods unless the interviewer wants a from-scratch implementation. Also, proactively mention edge cases and error handling to show maturity.

1. Clarify Requirements

Ask about the expected time complexity, whether the array is static or dynamic, and if operations should modify in-place or return a new array. Also clarify input types and error handling expectations.

2. Choose Data Structure

Decide between a simple array, dynamic array, linked list, or balanced BST based on the required time complexities. Explain your choice and its trade-offs.

3. Implement Operations

Write clean code for add, remove, and update, handling edge cases such as invalid indices, empty array, and resizing if necessary. Ensure each operation returns the modified array as required.

4. Analyze Complexity

State the time and space complexity for each operation and justify them. Discuss any optimizations or alternative approaches.

5. Test with Examples

Walk through a few test cases, including edge cases, to demonstrate correctness and robustness of your solution.

Key Points to Mention

  • Time complexity of each operation (add, remove, update) and how it depends on the chosen data structure.
  • Edge cases: invalid index, empty array, removing from empty array, updating non-existent index.
  • In-place vs. returning a new array: clarify and handle accordingly.
  • Trade-offs between different data structures (e.g., array vs. linked list vs. balanced BST).
  • Error handling: how to handle invalid inputs (e.g., throw exceptions or return error codes).
  • Space complexity and potential need for resizing (if using dynamic array).

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