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IMC·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

IMC quant engineer interview, one question that looked like a simple true/false but was actually testing whether you really understand exponential scaling. Felt a bit embarrassed by how long I sat on it.

Questions Asked (1)

Q1

True or false: a 64-bit integer can represent roughly two times more values than a 32-bit integer. Explain your reasoning.

Technical Trade-offsAlgorithms & Data Structures
Author's notes

My first instinct was to say 'false, it's way more than 2x' which is correct, but then I fumbled the actual explanation.

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AI HintsAI Generated

Suggested Approach

Start by stating that the statement is false, then explain that the number of values doubles with each additional bit, so a 64-bit integer represents 2^32 times more values than a 32-bit integer, not 2 times. Use the formula 2^n for n-bit integers and contrast the magnitudes to highlight the exponential growth.

Pro tip: Emphasize that the number of values doubles per bit, so the ratio between 64-bit and 32-bit is 2^32, which is about 4 billion—a common pitfall is to think linearly. This shows you understand exponential scaling, a key concept in systems design.

1. Clarify the statement

Restate the question to ensure understanding: 'The claim is that a 64-bit integer can represent roughly two times more values than a 32-bit integer.'

2. Recall the formula

State that an n-bit integer can represent 2^n distinct values (assuming unsigned; for signed, it's also 2^n values, just with a different range).

3. Compute the values

Calculate: 32-bit gives 2^32 ≈ 4.29 billion values; 64-bit gives 2^64 ≈ 1.84×10^19 values.

4. Compare the magnitudes

Find the ratio: (2^64) / (2^32) = 2^32 ≈ 4.29 billion. So a 64-bit integer represents about 4 billion times more values, not 2 times.

5. Conclude and explain

Conclude the statement is false, and explain that the number of values doubles with each additional bit, leading to exponential growth.

Key Points to Mention

  • Number of values for n bits is 2^n.
  • 32-bit: 2^32 ≈ 4.29×10^9 values.
  • 64-bit: 2^64 ≈ 1.84×10^19 values.
  • Ratio is 2^32 ≈ 4.29×10^9, not 2.
  • Each additional bit doubles the number of representable values.
  • Signed vs unsigned doesn't change the total count, only the range.

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