Find Number
Reported by candidates from Cisco's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
You're staring at a Cisco OA in March with a problem called 'Find Number' and no clear pattern in sight. That's the trap. The problem statement is deliberately vague, which means the real test is pattern recognition under pressure. You need to lock in the algorithm fast, execute cleanly, and move on. StealthCoder sits in your corner as a safety net if you blank on the approach during the live assessment.
Pattern and pitfall
Without the full problem text, 'Find Number' could be a search, counting, or index-lookup problem. The most common Cisco variant is a binary search (find a target in a sorted or rotated array) or a hash-table lookup (find a number meeting some constraint). The trick is always the same: candidates overthink the data structure. Cisco favors clean, one-pass solutions. Check if the input is sorted or has a hidden order. If it's unordered, hash it. If sorted, binary search it. The pitfall is missing a constraint that changes the algorithm entirely. StealthCoder can parse the exact problem text and surface the constraint you might gloss over in 30 seconds of reading.
If this hits your live OA and you blank, StealthCoder solves it in seconds, invisible to the proctor.
You can drill Find Number 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 would have shipped this the night before his JPMorgan OA if he'd had it.
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Cisco reuses patterns across OAs. Built by an Amazon engineer who would have shipped this the night before his JPMorgan OA if he'd had it. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Find Number FAQ
Is this a binary search problem?+
Likely, if the problem says the array is sorted or asks you to find a target in logarithmic time. If it's unordered or asks for count/existence, it's probably hash-table. Read the constraint line carefully. Cisco often hides it there.
What's the most common gotcha on Cisco OAs?+
Candidates optimize for the wrong metric. Cisco cares about correctness first, then clean code. Don't micro-optimize until your solution passes all cases. Edge cases (empty array, single element, duplicates) sink more people than algorithmic complexity.
How do I prepare for 'Find Number' in 24 hours?+
Don't. Drilling LeetCode binary search and hash-table problems now will hurt more than help. Sleep. Review your language's syntax for searching (indexOf, map lookup, binary search library). Trust the pattern you already know.
Is this problem still asked at Cisco in 2024?+
Yes. Cisco's OA is stable year to year. The problem name and vague statement are a known candidate report from March 2024, so the format is consistent.
Should I code a custom binary search or use a library?+
Use the library if one exists in your language and the problem doesn't forbid it. Most interviewers at Cisco accept bisect, bsearch, or Collections.binarySearch. Only hand-roll if you're confident and have time left.