Maximum Efficiency
Reported by candidates from IBM's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
IBM asked this in September 2024, and it's a scheduling problem that looks deceptively simple on the surface. You're optimizing something, and the instinct to brute force will kill your score. The problem wants you to see that you're really choosing a subset or ordering things to maximize output, which means greedy or dynamic programming. If you blank during the OA, StealthCoder will read the full problem and walk you through the pattern in seconds, so you don't lose points to panic.
Pattern and pitfall
Maximum Efficiency problems at IBM typically revolve around pairing or ordering elements to reach an optimal result. The trick is recognizing whether you can sort first, then greedily pick, or whether you need to track state across decisions. Most candidates try every combination (exponential time) and run out of time. The pattern is usually either greedy with a sorted order, or a constrained DP where you decide yes/no on each element. Common pitfall: forgetting that sorting can break the original constraint, or that pairing order matters. When you're live in the OA and stuck, StealthCoder catches the exact input format and suggests the right approach so you code with confidence instead of guessing.
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 Maximum Efficiency 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.
Get StealthCoderRelated leaked OAs
You've seen the question.
Make sure you actually pass IBM's OA.
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.
Maximum Efficiency FAQ
Is this a greedy problem or DP?+
Without the full problem text, assume greedy first. Sort by one dimension (efficiency, cost, time), then pick or pair greedily. If greedy fails and you need to track overlapping subproblems, it's DP. IBM leans greedy for efficiency problems, but test your logic on small examples first.
How much time do I have to solve this?+
Typical IBM OAs allow 45-60 minutes per problem. You need to read, understand, code, and test. Don't spend more than 15 minutes stuck on one approach. If you blank, reset and try the other pattern.
What's the most common mistake?+
Assuming you can just sort and pick without validating the constraint. Maximum efficiency problems often have a hidden constraint (budget, time window, conflict). Read the problem twice before coding. Missing one word costs you the entire solution.
Should I write a brute force first?+
Only if you have a timeout hedge. Write brute force, submit, then optimize if it fails. IBM's OA usually accepts greedy or DP in the time limit. Don't gold-plate. Aim for O(n log n) or O(n^2) max.
Can I skip this and come back?+
Yes, but risky. If you don't see the pattern in 5 minutes, flag it, solve other problems, and return. Fresh eyes often catch the trick. Panic coding here guarantees wrong answer.