Convert a Number to Hexadecimal
A easy-tier problem at 51% community acceptance, tagged with Math, Bit Manipulation. Reported in interviews at tcs and 0 others.
You're staring at a number-to-hex conversion problem and thinking it should be trivial. Then you hit negative numbers and realize the straightforward approach breaks. TCS and a handful of other shops ask this one to separate candidates who understand two's complement from those who don't. The trick isn't complex, but it's easy to miss under pressure. With a 51% acceptance rate, plenty of engineers stumble here. If this lands in your live OA and you blank on the bit manipulation pattern, StealthCoder solves it in seconds while you stay invisible to the proctor.
Companies that ask "Convert a Number to Hexadecimal"
Convert a Number to Hexadecimal is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by a senior engineer who knows the OA is theater. This is the script.
Get StealthCoderThe problem forces you to handle signed integers, particularly negatives. Most people default to converting the absolute value and prepending a minus sign, which fails on two's complement representation. The real solution treats negative numbers as their unsigned 32-bit equivalents, then extracts hex digits from the least significant nibble upward. The key insight: for a negative number like -1, its unsigned 32-bit representation is 4294967295 (0xFFFFFFFF), and you extract one nibble at a time using modulo 16 and division. Common pitfall: ignoring leading zeros or trying to handle the sign separately. The Bit Manipulation topic here is the actual strategy, not just bit-shifting tricks. When you hit this live and can't recall whether Java's Integer.toHexString handles negatives correctly, StealthCoder delivers the pattern without drama.
Pattern tags
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Convert a Number to Hexadecimal recycles across companies for a reason. It's easy-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by a senior engineer who knows the OA is theater. This is the script. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Convert a Number to Hexadecimal interview FAQ
Is this problem actually easy or is the 51% acceptance rate misleading?+
It's easy algorithmically but trips people on edge cases. The difficulty spike comes from negative numbers and two's complement, not the core logic. Most who fail either don't test negatives or mishandle the bit representation. Candidates familiar with bit manipulation usually pass quickly.
Do I really need to understand two's complement to solve this?+
Yes. The problem requires converting signed integers to their unsigned hex equivalents. Without understanding two's complement, you'll hardcode workarounds that fail. TCS and similar companies test this specifically to verify you understand number representation at the bit level.
What's the gotcha that makes people fail even after they understand the logic?+
Forgetting to handle the case where the input is 0, or dropping leading zeros unintentionally. Some candidates also loop forever or produce incorrect output for negative numbers because they assume standard signed conversion. Testing -1 and 0 catches most bugs.
Does this relate directly to the Bit Manipulation topic or is that just categorization?+
Both. Bit Manipulation is the core strategy here. You use modulo 16 and integer division to extract nibbles, which is a bitwise extraction pattern. Math is secondary; the real skill being tested is comfortable manipulation of bits and unsigned representation.
Should I memorize hex conversion or derive it during the interview?+
Derive it. The modulo-and-divide approach is faster to code and less error-prone than memorization. Walk through one example (like -1 to 'ffffffff') before you start, then implement. That demonstration signals you understand the mechanism, not just the answer.
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