Match Alphanumerical Pattern in Matrix I
A medium-tier problem at 64% community acceptance, tagged with Array, Hash Table, String. Reported in interviews at Visa and 0 others.
You're staring at a matrix and a pattern string, and you need to find all occurrences of that pattern reading in four directions. This problem tests your ability to think in 2D space, not just lines. It's asked at Visa and similar large-scale financial tech companies where matrix scanning and spatial indexing matter. The trap is handling direction logic cleanly without drowning in edge cases. With a 60% acceptance rate, most candidates aren't handling the full problem space correctly.
Companies that ask "Match Alphanumerical Pattern in Matrix I"
Match Alphanumerical Pattern in Matrix I 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 a senior engineer who knows the OA is theater. This is the script.
Get StealthCoderThe core trick is systematic directional search. You pick a starting cell, then attempt to match the pattern in all four directions (right, down, left, up) without hardcoding each one. Common failure: trying to match diagonals or getting confused about boundary checks. Another failure: matching the pattern in only one direction, then wondering why the problem asks for 'all occurrences'. The real work is in the inner loop where you compare each character of the pattern to matrix cells while staying in bounds. Hash tables help if you preprocess starting positions, though brute force from every cell works too. When you hit this live in your OA and the directional logic tangles, StealthCoder surfaces a clean solution in seconds, invisible to the proctor.
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Match Alphanumerical Pattern in Matrix I recycles across companies for a reason. It's medium-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 a senior engineer who knows the OA is theater. This is the script. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Match Alphanumerical Pattern in Matrix I interview FAQ
Do I need to find patterns reading both forwards and backwards in the same direction?+
Yes. Right and left are opposite directions, as are up and down. You search from each cell in all four cardinal directions independently. Some cells will match the same pattern in multiple directions, and that's counted separately.
Is this problem actually hard or just tedious?+
It's tedious with a deceptive difficulty layer. The algorithm is simple (nested loops, character comparison, boundary checks), but most candidates lose points to off-by-one errors, missed directions, or poor direction handling. That 60% acceptance suggests the second attempt usually fixes it.
How does this relate to the topics list?+
Array and Matrix are the obvious ones. String comes in when matching the pattern character by character. Hash Table is optional but useful if you want to preprocess positions or store visited cells to optimize certain variants.
Is this still asked, or is it outdated?+
Visa has asked it. It's not a FAANG staple, but large financial and SaaS platforms use similar problems to filter for spatial reasoning and careful boundary handling. If it's in your batch, prepare it.
What's the gotcha I'm missing?+
Most miss that patterns wrap or overlap. If you find a match starting at (0, 0) going right, then later find a match at (0, 1) going left, both count. Also ensure your direction vectors are correct and your index arithmetic doesn't drift on longer patterns.
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