Find Min Transitions
Reported by candidates from TikTok's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
You've got a TikTok OA incoming with 'Find Min Transitions' and no obvious pattern hint. This is a state-machine or greedy optimization problem where you're minimizing the number of times something flips or changes. The trick is figuring out what the state actually is and whether a greedy or dynamic-programming approach wins. If you blank on the exact algorithm during the OA, StealthCoder reads the full problem and feeds you the pattern in real time, so you're never starting from zero.
Pattern and pitfall
Without the full problem text, 'min transitions' typically means you're moving through states (array indices, graph nodes, binary digits, or configuration states) and counting how many times the state property changes. The pattern is usually either greedy (make the locally optimal choice at each step) or DP (track the minimum cost to reach each state). Common variants include: minimizing bit flips in a binary sequence, minimizing color changes in a string, or finding the cheapest path through a state graph. The pitfall is overthinking when greedy works, or missing state definition. During the live OA, if the problem statement is ambiguous, StealthCoder will clarify the exact state space and let you code with confidence.
The honest play: practice the pattern, and have StealthCoder ready for the one you didn't see coming.
You can drill Find Min Transitions 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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TikTok reuses patterns across OAs. Built for the candidate who saw this exact problem leak two days before his OA and wondered if anyone had a play. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Find Min Transitions FAQ
Is this a DP problem or greedy?+
Usually both are possible, but greedy is faster if the problem has optimal substructure and you can prove a local choice never needs backtracking. If the problem asks for a global minimum across multiple overlapping choices, default to DP with memoization. Test greedy on the examples first.
What does 'transition' mean here?+
A transition is a change from one state to another. If the input is an array, it's often a change in value or property between consecutive elements. If it's a bit string, it's a 0-to-1 or 1-to-0 flip. Read the problem carefully; the state definition is the key.
How do I handle the state representation?+
Define your state clearly: what property are you tracking, and when does it change. For arrays, track the last value seen. For graphs or sequences, track position and property. Use a dictionary or tuple to represent state if multi-dimensional. This clarity prevents off-by-one and logic errors.
What if I have multiple valid answers?+
The problem asks for the minimum count, so there's one correct integer answer. If multiple paths give the same min, you likely only need the count, not the path itself. Verify with the examples whether you need to return the transitions or just the count.
How much time should I spend on this in the OA?+
15-20 minutes to understand the state, 10 minutes to code, 5 minutes to test on examples. If you're stuck on state definition after 10 minutes, use StealthCoder to re-read and clarify the problem, then pivot to code. Don't waste 30 minutes on interpretation.