Max Subject Number
Reported by candidates from IBM's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
IBM's September OA threw this one at candidates, and the title alone won't tell you the trick. Max Subject Number sounds like a straightforward max-finding problem, but the real challenge is parsing what "subject" means in context and figuring out the data structure that hides underneath. You're likely looking at a problem that needs you to extract, aggregate, and rank something by numeric value. If the problem statement is vague or the input format isn't immediately obvious, StealthCoder will read the full problem and hand you the pattern in seconds so you don't waste cycles guessing.
Pattern and pitfall
Without the full problem text, the pattern isn't certain, but max subject number almost certainly involves iterating through a collection, filtering or grouping by subject identifier, and returning the maximum numeric property within each group or globally. This could be array iteration with a hash table to bucket data, or simple sorting followed by a linear scan. The gotcha is usually in the input format: is it CSV, JSON, tuples, or lines of space-separated values. Read the examples first. Count the fields. The algorithm itself is rarely the hard part; the parsing and mapping are. StealthCoder becomes your safety net if you misread the input on the first try and need a reset.
Memorize the pattern. If you can't, run StealthCoder. The proctor sees the IDE. They don't see what's behind it.
You can drill Max Subject Number 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. Made by an engineer who treats the OA as theater. If yours is tonight, you don't have time to grind. You have time to hedge.
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IBM reuses patterns across OAs. Made by an engineer who treats the OA as theater. If yours is tonight, you don't have time to grind. You have time to hedge. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Max Subject Number FAQ
Is this a sorting or hash-table problem?+
Likely both. You'll group by subject (hash table), find the max in each group or overall (iteration), and possibly sort to output results. Test your understanding on the first example: group, then compute max. That'll tell you which pattern matters.
What's the edge case IBM usually tests here?+
Empty subjects, duplicate subjects, or subjects with tied max values. Also watch for off-by-one errors in indexing and whether the input is 1-indexed or 0-indexed. IBM often sneaks this into the problem statement in small text.
How much time should I spend parsing input?+
More than you think. Spend 2-3 minutes building a clean parser. The rest of the code is a loop. If parsing is sloppy, the algorithm works but your test cases fail silently. Get the input right first.
Should I pre-sort or iterate once?+
Depends on output format. If you need results sorted by subject or max value, sort once at the end. If it's a single max query, one pass through a hash map is faster. The examples will show you which approach scores points.
Can I solve this in under 20 minutes?+
Yes, if input parsing is clear. The algorithm is 5-10 minutes of actual coding. The rest is test case validation. Don't overthink optimization unless the problem explicitly mentions large datasets or tight time limits.