Find Largest Sum of Continuous Sequence
Reported by candidates from Cisco's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
Cisco asked this in September 2024 and it's a direct play on the maximum subarray pattern. You get an array, you find the contiguous slice with the highest sum. Sounds simple until you realize a naive nested loop will timeout. The trick is Kadane's algorithm, a single pass that tracks the best sum ending at each position. If you blank on the math during the OA, StealthCoder runs invisibly and gives you the pattern in real time so you can code instead of panicking.
Pattern and pitfall
Kadane's algorithm is the only way to solve this efficiently in O(n) time. At each element, you decide: extend the current sequence or start fresh. If the running sum goes negative, drop it and reset. Track the global maximum as you go. The pitfall is off-by-one errors or resetting the max at the wrong time. Most candidates over-engineer with dynamic programming when Kadane is a single loop. The problem text is missing here, so you'll need to watch for edge cases: negative-only arrays (answer is the least negative number), empty arrays, or single elements. StealthCoder catches these nuances live because it reads your actual problem statement on screen.
Drill it cold or hedge it with StealthCoder. Either way, don't walk into the OA hoping you remember the trick.
You can drill Find Largest Sum of Continuous Sequence 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. Made for the candidate who got the OA invite this morning and has 72 hours, not six months.
Get StealthCoderRelated leaked OAs
This OA pattern shows up on LeetCode as maximum subarray. If you have time before the OA, drill that.
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Make sure you actually pass Cisco's OA.
Cisco reuses patterns across OAs. Made for the candidate who got the OA invite this morning and has 72 hours, not six months. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Find Largest Sum of Continuous Sequence FAQ
Is this really just Kadane's algorithm or is there a trick?+
It's Kadane's, but the trick is knowing when to reset. If your running sum becomes negative, you drop it only if the next element alone is larger. Don't reset to zero carelessly. Practice the state transitions once, memorize them, and you're done.
What if all numbers in the array are negative?+
Your answer is the least negative number, i.e., the single largest element. Kadane still works because max_ending_here and global_max both start at the first element. This catches a lot of people off guard.
How do I prepare for this in 48 hours if I've never seen it?+
Code Kadane's algorithm once on paper or in a sandbox. Trace it through a small example with both positive and negative numbers. The logic is simple, muscle memory matters more than theory here.
Does Cisco ask for the subarray itself or just the sum?+
The title says sum, so you're probably returning an integer. If they ask for indices or the actual subarray, that's a follow-up. Have a version ready that tracks start and end indices, but start with the sum.
Will this show up again in future Cisco OAs?+
Yes. This is a canonical problem. Cisco uses it regularly. If you see it, you should solve it clean in under 5 minutes. It's a warm-up question most of the time.