Reverse An Integer
Reported by candidates from Microsoft's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
You've got a Microsoft OA in your inbox with an integer reversal problem. November 2024 candidates reported this one. It looks simple on the surface, flip the digits, but there's a catch that trips people up in live interviews. The real question isn't how to reverse; it's what happens at the boundaries. StealthCoder reads the problem in real time and shows you the edge cases you'd otherwise miss or blank on under pressure.
Pattern and pitfall
Reverse an integer means you take a number like 123 and return 321. The trap is overflow. If the reversed number exceeds the 32-bit signed integer range (roughly -2.1 billion to 2.1 billion), you return 0. Most candidates code the reversal quickly but forget to validate the result before returning it. Build the answer digit by digit, checking after each digit whether you'd overflow if you added the next one. This isn't really a two-pointers problem in the classic sense, it's arithmetic with boundary validation. StealthCoder gives you the overflow check pattern so you don't code a "working" solution that fails the hidden test cases.
The honest play: practice the pattern, and have StealthCoder ready for the one you didn't see coming.
You can drill Reverse An Integer cold, or you can hedge it. StealthCoder runs invisibly during screen share and surfaces a working solution in under 2 seconds. The proctor sees the IDE. They don't see what's behind it. Built for the candidate who saw this exact problem leak two days before his OA and wondered if anyone had a play.
Get StealthCoderRelated leaked OAs
This OA pattern shows up on LeetCode as reverse integer. If you have time before the OA, drill that.
You've seen the question.
Make sure you actually pass Microsoft's OA.
Microsoft reuses patterns across OAs. Built for the candidate who saw this exact problem leak two days before his OA and wondered if anyone had a play. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Reverse An Integer FAQ
Is this actually a two-pointer problem?+
Not in the traditional sense. You're extracting digits and rebuilding the number mathematically. Two-pointers was likely a misclassification by the reporter. Focus on the modulo/division pattern and overflow detection, not pointer swapping.
What's the overflow trick everyone misses?+
Before adding the next digit to your result, check if result > INT_MAX / 10 or (result == INT_MAX / 10 and digit > 7). Same logic for negatives. Build defensively, don't patch after.
Do I need to handle negative numbers separately?+
No. Store the sign, reverse the absolute value, then reapply the sign. Or handle the sign inside your reversal loop. Either works. The overflow logic applies to the magnitude regardless.
How long should this solution take to code live?+
5-8 minutes for the core logic if you've seen the pattern. Another 2-3 minutes to add overflow checks correctly. If you're unsure about the bounds, that's where a real-time assist helps you not panic.
Is Microsoft still asking this in November 2024?+
Yes, it was reported in mid-November. It's a classic screening problem. Expect it on your OA. The simplicity is the trap. They're testing whether you think about edge cases, not whether you can do basic math.