Count Number of Teams
A medium-tier problem at 70% community acceptance, tagged with Array, Dynamic Programming, Binary Indexed Tree. Reported in interviews at IBM and 1 others.
Count Number of Teams is a medium-difficulty array problem that looks simple on paper but trips up candidates who don't spot the pattern. IBM and Goldman Sachs both ask it. The 70% acceptance rate masks a sharp divide: candidates who see the trick solve it cleanly in minutes, others spin on brute force and run out of time. The problem asks you to count ordered triplets where the middle element acts as a pivot. If you blank on the approach during your live assessment, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Count Number of Teams"
Count Number of Teams 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. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoderThe naive read is to check all triplets, which works but screams O(n^3). The real insight is that for each middle element, you count how many smaller elements to its left multiply by how many larger elements to its right (and vice versa). This flips the problem into O(n^2), which is acceptable but not optimal. The dynamic programming angle involves precomputing left and right contribution counts. For harder constraints or stronger signals, a Binary Indexed Tree or Segment Tree cuts it to O(n log n), but most candidates won't need that unless the interviewer pushes. The gotcha is confusing the direction of the inequality or forgetting that strictly less/greater matters. During a live OA, if you're unsure whether to optimize past O(n^2), StealthCoder removes the guessing and hands you a clean working solution.
Pattern tags
You know the problem.
Make sure you actually pass it.
Count Number of Teams 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. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Count Number of Teams interview FAQ
Is this really asked at IBM and Goldman Sachs?+
Yes. Both companies have reported it. It's a signals-based medium that filters for pattern recognition and dynamic thinking. Not as flashy as hard DP problems, but it's a real fingerprint for these shops.
Do I need to code Binary Indexed Tree to pass?+
No. An O(n^2) solution counting left and right contributions clears the acceptance threshold. BIT is a stretch goal if you want to impress or if the interviewer hints at tighter time complexity.
What's the main trick I'll miss if I haven't seen it before?+
Not realizing you can pivot on each middle element and count contributions independently. Most people chase brute-force triplet enumeration and lose time. Once you see the pivot idea, it clicks.
How does this relate to the other topics listed?+
Array is the input format. Dynamic Programming is the standard O(n^2) approach. Binary Indexed Tree and Segment Tree are advanced optimizations. You won't need them unless you're aiming for polish or get explicitly asked to optimize further.
Is 70% acceptance rate high or low for medium?+
It's above average for medium. Tells you most people who attempt it solve it, but it's not a gimme. The people who blank are the ones who didn't drill the pivot insight before walking into the assessment.
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