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Seems trivial until you sit with the constraints.
Clarify the problem constraints and edge cases, then discuss a mathematical approach to reverse digits using modulo and division. Emphasize handling negative numbers and potential overflow, even though the input range is limited. Write clean code and test with examples.
Pro tip: Mention that the input range is within 16-bit signed integer, so the reversed number will also fit in 32-bit integer, but still discuss overflow in general. Show awareness of integer division and modulo behavior with negative numbers in different languages.
Ask about input range, negative numbers, trailing zeros, and whether the reversed number should preserve sign. Confirm that the function should return an integer.
Use a loop to extract digits from the end using modulo 10 and build the reversed number by multiplying by 10 and adding the digit. Handle negative numbers by working with absolute value and reapplying sign.
Write code that initializes reversed to 0, iterates while the number is not 0, updates reversed, and reduces the number by integer division by 10. For negative numbers, take absolute value first and then negate the result.
Test with positive numbers (e.g., 123 -> 321), negative numbers (e.g., -123 -> -321), numbers ending with zero (e.g., 120 -> 21), and boundary values like 32767 and -32768.
State that time complexity is O(log10(n)) and space is O(1). Mention alternative string-based approach and its trade-offs (simplicity vs. efficiency).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.