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Meta·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

Meta SWE coding round, one question on string manipulation. Pretty standard stuff but the edge cases are where they get you.

Questions Asked (1)

Q1

Given a string, determine whether it can become a palindrome by removing at most one character.

Algorithms & Data Structures
Author's notes

Looks easy until you start coding it up.

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AI HintsAI Generated

Suggested Approach

Use a two-pointer technique starting from both ends of the string. When characters mismatch, check if skipping either the left or right character results in a palindrome. If either does, return true; otherwise, return false.

Pro tip: Always clarify edge cases like empty string or single character, and mention that you'll handle them upfront. Also, discuss the time and space complexity (O(n) time, O(1) space) to show efficiency awareness.

1. Clarify and handle edge cases

Confirm the definition of a palindrome and ask about input constraints (e.g., empty string, single character). State that these cases return true.

2. Initialize two pointers

Set left pointer at the start and right pointer at the end of the string. Iterate while left < right.

3. Compare characters and handle mismatch

If characters at left and right match, move both pointers inward. If they don't match, check if skipping either character yields a palindrome.

4. Implement helper function to check palindrome

Create a helper that checks if a substring (from left to right) is a palindrome using two pointers. Use it when a mismatch occurs.

5. Return result and analyze complexity

Return true if either skip leads to a palindrome, else false. Mention O(n) time and O(1) space complexity.

Key Points to Mention

  • Two-pointer technique for efficient traversal
  • Handling the mismatch by checking both possibilities (skip left or skip right)
  • Helper function to verify palindrome on a substring
  • Time complexity: O(n) because each character is visited at most twice
  • Space complexity: O(1) as no extra data structures are used
  • Edge cases: empty string, single character, already palindrome, multiple mismatches

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