Find Winner on a Tic Tac Toe Game
A easy-tier problem at 54% community acceptance, tagged with Array, Hash Table, Matrix. Reported in interviews at Zoho and 2 others.
You're two minutes into a Tic Tac Toe validator problem and your brain's already halfway through a nested loop mess. This problem shows up on assessments for Zoho, Qualcomm, and Tesla. It's labeled easy, but the acceptance rate hovers just above 54%, which means half the candidates who attempt it either overcomplicate the logic or miss edge cases in their win-check. The trick isn't the difficulty of the code, it's keeping the logic clean enough to ship without bugs in real time. StealthCoder is your safety net if you freeze on the state validation.
Companies that ask "Find Winner on a Tic Tac Toe Game"
Find Winner on a Tic Tac Toe Game is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop.
Get StealthCoderThe core challenge is evaluating board state efficiently without unnecessary iteration. Most candidates default to checking all rows, columns, and diagonals every time, which works but leaves room for indexing errors and redundant computation. The actual pattern: track the last move and only validate the winning condition along that piece's row, column, and diagonals. This cuts your search space and reduces bug surface. Common pitfall is handling the draw state, if the board is full and no winner exists, return 'Draw', not an error. Array and Matrix operations are straightforward here, but Hash Table patterns emerge if you're tracking move counts or state transitions across multiple game states. StealthCoder surfaces the clean validation path in seconds if you hit the wall during live assessment.
Pattern tags
You know the problem.
Make sure you actually pass it.
Find Winner on a Tic Tac Toe Game recycles across companies for a reason. It's easy-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Find Winner on a Tic Tac Toe Game interview FAQ
Is this really an easy problem if 46% of candidates fail it?+
Yes. The algorithm is trivial, but the bugs are subtle. Off-by-one errors in diagonal checks, forgetting the draw condition, or validating the entire board instead of just the last move cause failures. Once you've written it clean once, it's muscle memory. The 54% acceptance reflects implementation slips, not conceptual difficulty.
Do I need to optimize for performance on this one?+
No. The board is always 3x3, so brute force checking all rows, columns, and diagonals takes constant time. Optimization gains are negligible. Write for correctness and clarity. Zoho, Qualcomm, and Tesla are hiring engineers, not micro-optimizers on tiny inputs.
What's the trick with the draw state?+
The board can be full without a winner. Your function must return 'Draw' explicitly when all nine cells are filled and no three-in-a-row exists. Forgetting this edge case is the second-most common failure. Check board fullness after validating win conditions.
Should I validate both players or assume the input is legal?+
Assume the input is a valid game state. You don't need to verify move order or that only two distinct players are present. Your job is to read the final board and determine the outcome. Checking assumptions wastes time in a live assessment.
How does this relate to the Matrix and Hash Table topics listed?+
Matrix is the board representation itself, 2D array access. Hash Table applies if you're tracking board state across multiple games or caching results, though that's overkill here. Focus on clean 2D array iteration and win-condition logic. Keep it simple.
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