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IMC·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

IMC software engineer interview with a data structures and complexity question. Pretty focused on fundamentals, the kind of thing you either know cold or you fumble through.

Questions Asked (1)

Q1

What is the worst-case time complexity for each of these four operations: removing an element from a sorted array, checking if a key exists in a hash table, removing the minimum element from a min-heap, and finding the i-th element in a sorted array?

Algorithms & Data Structures
Author's notes

Four-parter in one question, which I wasn't expecting.

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AI HintsAI Generated

Suggested Approach

For each operation, identify the underlying data structure and the worst-case scenario that leads to the highest time complexity. State the complexity clearly and briefly justify it by explaining the operation's mechanics.

Pro tip: Mention that these are worst-case complexities and that average-case or amortized complexities can differ, showing awareness of practical performance.

1. Identify the data structure and operation

For each of the four operations, note the data structure involved and what the operation entails.

2. Determine the worst-case scenario

Think about the least favorable configuration or state of the data structure that maximizes the time taken.

3. Derive the time complexity

Based on the worst-case scenario, express the number of basic steps as a function of input size n, using Big-O notation.

4. Justify briefly

Provide a one-sentence explanation for each complexity to demonstrate understanding.

Key Points to Mention

  • Removing an element from a sorted array: O(n) due to shifting elements to fill the gap.
  • Checking if a key exists in a hash table: O(n) worst-case when all keys collide, though average is O(1).
  • Removing the minimum element from a min-heap: O(log n) because it requires reheapification (sift-down).
  • Finding the i-th element in a sorted array: O(1) via direct indexing.
  • Distinguish between worst-case and average-case complexities where relevant.
  • Mention that hash table worst-case can be avoided with good hash functions and collision resolution strategies.

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