Get Minimum Operation Count
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 candidates walked out uncertain. Get Minimum Operation Count is asking you to find the fewest steps to reach a goal state, which means you're either counting operations, simulating state transitions, or optimizing a sequence. The trick is knowing whether this is a math problem (direct formula), a greedy problem (local choice at each step), or a graph search (BFS to explore all paths). StealthCoder will read the problem on screen and surface the pattern instantly if you freeze mid-interview.
Pattern and pitfall
Without the full problem text, the pattern is likely greedy, math, or breadth-first-search. Most "minimum operation" problems have a greedy solution (always pick the locally optimal choice) or require BFS to guarantee the global minimum. The trap is over-complicating it with dynamic programming when a simple greedy or mathematical formula works. The other trap is misunderstanding the state space: are operations transforming a number, a string, a set? That changes everything. During the OA, read the constraints and examples ruthlessly. If operations are commutative and simple, greedy wins. If order matters or the state space is hidden, BFS is your hedge.
The honest play: practice the pattern, and have StealthCoder ready for the one you didn't see coming.
You can drill Get Minimum Operation Count 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.
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Get Minimum Operation Count FAQ
What makes 'minimum operation' problems hard?+
You don't know upfront whether the answer is a formula, a greedy choice, or a search. The problem text will specify the operation (add 1, divide by 2, etc.). Read that first. Then ask: does order matter? Can I work backwards? If yes to either, BFS. If not, try greedy or math.
How much time should I spend before coding?+
3-5 minutes on the examples. Trace through by hand. Write down the operations and count. If a pattern jumps out (like halving a number is always optimal), you're greedy. If not, BFS is safer. Code a rough solution in 10 minutes, test on the examples, refine.
Is this still asked at IBM after September?+
Yes. Operation-counting and state-space problems are evergreen in tech interviews. IBM uses them to test optimization thinking. The exact title or numbers change, but the pattern stays.
What's the most common pitfall?+
Assuming greedy is correct without proving it on the examples. Always verify with at least two test cases. If your greedy solution works but the explanation feels shaky, pivot to BFS to be safe during the OA.
Can I brute-force this?+
Depends on constraints. If the goal is small (under 100 or 1000), BFS will finish fast. If the goal is huge (10^9), you need math or greedy. Read the constraints closely in the real OA.