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Google·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

Google SWE interview with a string manipulation problem. Pretty standard stuff but worth logging for anyone prepping.

Questions Asked (1)

Q1

Write a function to reverse the words in a sentence.

Algorithms & Data Structures
Author's notes

Seemed easy at first and I jumped straight to splitting on spaces, but then they pushed on edge cases like multiple spaces between words and leading/trailing whitespace.

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AI HintsAI Generated

Suggested Approach

Clarify the definition of 'word' and edge cases, then propose an in-place two-step approach: reverse the entire string, then reverse each word individually. Discuss time and space complexity, and consider alternative approaches like using a stack or split/join for comparison.

Pro tip: At Google, interviewers value clean, efficient code and clear communication. Before coding, explicitly state your assumptions (e.g., words separated by single spaces, no leading/trailing spaces) and ask if in-place modification is required, as this shows attention to detail and scalability.

1. Clarify requirements and edge cases

Ask about input format (e.g., string vs. char array), definition of a word, handling of multiple spaces, punctuation, and empty strings. Confirm if in-place reversal is desired and if extra space is allowed.

2. Outline the approach

Explain the two-step in-place method: first reverse the entire string, then reverse each word. Alternatively, mention using split/join or a stack, and discuss trade-offs.

3. Walk through an example

Use a simple example like 'hello world' to demonstrate the steps: reverse whole string to 'dlrow olleh', then reverse each word to 'world hello'.

4. Implement the solution

Write clean code with helper functions for reversing a range. Handle edge cases like empty strings or single words. Use two pointers for in-place reversal.

5. Analyze complexity and test

State time complexity O(n) and space complexity O(1) for in-place. Test with edge cases: empty string, multiple spaces, punctuation, and long words.

Key Points to Mention

  • Time and space complexity analysis (O(n) time, O(1) space for in-place).
  • Handling multiple spaces and preserving word order.
  • In-place vs. using extra space (e.g., split/join) and trade-offs.
  • Edge cases: empty string, single word, leading/trailing spaces.
  • Definition of a word (e.g., sequences separated by spaces).
  • Code readability and modularity (helper functions).

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