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Microsoft·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jul 2026

Summary

Microsoft SWE coding round, one question on text justification. Pretty focused session, nothing conversational about it.

Questions Asked (1)

Q1

Write a function that takes a list of words and a maximum line width, and returns the words formatted with full justification.

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

Looks straightforward until you actually start coding it.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem: define full justification (left-align last line, distribute spaces evenly, handle edge cases like single word or word longer than width). Then outline a greedy algorithm: pack words into lines, then justify each line except the last. Finally, discuss time/space complexity and potential optimizations.

Pro tip: Mention that you would handle edge cases like a single word on a line (left-align) and words longer than maxWidth (though typically not allowed) to show thoroughness. Also, note that the greedy approach is optimal for this problem.

1. Clarify requirements and edge cases

Ask about assumptions: can words be longer than maxWidth? Should the last line be left-aligned? How to distribute extra spaces when not evenly divisible? Confirm that full justification means text is aligned to both left and right margins.

2. Design greedy line packing

Iterate through words, adding them to the current line as long as the total length (including at least one space between words) does not exceed maxWidth. When adding the next word would exceed, finalize the current line.

3. Justify each line except the last

For each line, calculate the total spaces needed to reach maxWidth. Distribute spaces as evenly as possible between words, with extra spaces going to the leftmost gaps. If only one word, left-align it (pad right with spaces).

4. Handle the last line

Left-align the last line: join words with a single space and pad the right with spaces to reach maxWidth.

5. Analyze complexity and discuss trade-offs

State that the algorithm runs in O(n) time where n is total characters, and O(n) space for the output. Discuss potential variations like using a different justification strategy (e.g., minimizing raggedness) and why greedy is suitable here.

Key Points to Mention

  • Greedy algorithm for line packing: always fit as many words as possible per line.
  • Space distribution: divide total spaces by (number of words - 1), distribute remainder to leftmost gaps.
  • Edge cases: single word on a line (left-align), last line (left-align), words longer than maxWidth (if allowed, handle separately).
  • Time and space complexity: O(n) time and O(n) space, where n is total characters in output.
  • Trade-offs: greedy is optimal for this problem; alternative approaches like dynamic programming for minimizing raggedness are overkill.
  • Code clarity: use helper functions for justifying a line and for distributing spaces.

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