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Meta·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say
Jun 2026

Summary

Got a Meta coding screen with a sliding window problem. Pretty standard stuff, nothing too wild.

Questions Asked (1)

Q1

Given an integer array and an integer k, find the contiguous subarray of length k with the maximum average value and return it.

Algorithms & Data Structures
Author's notes

Classic sliding window, you compute the sum of the first k elements then slide across the array updating the sum as you go.

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AI HintsAI Generated

Suggested Approach

Use a sliding window of size k to compute the sum of each contiguous subarray, tracking the maximum sum and its starting index. Return the subarray corresponding to the maximum sum.

Pro tip: Avoid floating-point division by comparing sums directly; only divide at the end to return the average if needed. This prevents precision issues and improves performance.

1. Clarify requirements

Confirm that the array contains integers, k is positive and ≤ array length, and that we need to return the subarray (not just the average).

2. Initialize sliding window

Compute the sum of the first k elements and set it as the initial maximum sum. Record the starting index (0).

3. Slide the window

Iterate from index k to the end, updating the window sum by subtracting the element leaving the window and adding the new element. If the new sum exceeds the maximum, update the maximum and record the new starting index.

4. Return result

After the loop, extract the subarray from the recorded starting index of length k and return it. Optionally compute the average by dividing the maximum sum by k.

Key Points to Mention

  • Sliding window technique for O(n) time complexity
  • Avoiding floating-point arithmetic by comparing sums
  • Handling edge cases: k equals array length, k=1, negative numbers
  • Space complexity: O(1) extra space (excluding output)
  • Returning the subarray, not just the average
  • Potential follow-up: what if k is not fixed? (e.g., maximum average subarray of any length)

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