Min Operations Required
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 included a Min Operations Required question that tests your ability to work backwards from a target state. You're given a number and a set of allowed operations, and you need to find the minimum count of moves to reach a goal. This is a classic BFS or dynamic programming problem disguised as an optimization puzzle. If you've never seen this pattern before, it's easy to burn 20 minutes on the wrong approach. StealthCoder reads the problem in real time and surfaces the correct method so you don't guess.
Pattern and pitfall
The core pattern here is either breadth-first search (if the state space is manageable) or dynamic programming (if you can build up from the goal backwards). Most candidates default to greedy, which fails. The trick: think of it as a graph where each state is reachable via specific operations, and you're finding the shortest path. BFS guarantees the minimum. If the numbers are large, you may need DP with memoization to avoid timeout. The common pitfall is simulating operations forward instead of exploring all reachable states in parallel. StealthCoder acts as your safety net during the live assessment, keeping you from going down a greedy rabbit hole when the OA timer is burning.
If you see this problem in your OA tomorrow, the play is to recognize the pattern in 30 seconds. StealthCoder buys you that recognition.
You can drill Min Operations Required 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 by an Amazon engineer who passed his OA cold and still thinks the filter is broken.
Get StealthCoderRelated leaked OAs
This OA pattern shows up on LeetCode as integer replacement. If you have time before the OA, drill that.
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IBM reuses patterns across OAs. Built by an Amazon engineer who passed his OA cold and still thinks the filter is broken. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Min Operations Required FAQ
Is this asking me to reduce a number to 1, or reach a target?+
Check the problem statement carefully. If it's 'reduce N to 1 using operations like divide by 2 or subtract 1', that's the classic BFS/DP pattern. If it's 'reach a specific target', same logic applies. The structure tells you the algorithm.
Should I use BFS or DP for this?+
BFS if the state space is small enough (under 10^6 states). DP with memoization if you can express the problem as overlapping subproblems. Both will work, but BFS is usually simpler to code under pressure. Test with the constraints given.
What's the greedy trap everyone falls into?+
Trying to pick the 'best' operation at each step based on local optimization. That doesn't work here because some paths that look bad early lead to fewer total steps. You need to explore all paths in parallel, which is what BFS does.
How do I avoid timeout on large numbers?+
Don't simulate every single state if you don't have to. Use memoization so you never compute the same subproblem twice. If numbers are huge, look for mathematical patterns or shortcuts in the operations.
How much time should this take to code?+
If you recognize the BFS pattern immediately, 8-12 minutes. If you need to backtrack from greedy, 20-30 minutes. IBM's OAs typically give you 45-60 minutes per problem, so you have room, but the first 3 minutes of pattern recognition matter.