Count Equal and Divisible Pairs in an Array
A easy-tier problem at 84% community acceptance, tagged with Array. Reported in interviews at zeta suite and 1 others.
Count Equal and Divisible Pairs is an easy array problem with an 84% acceptance rate, reported by Bloomberg and Zeta Suite. It's the kind of problem that looks straightforward until you misread the constraints and burn minutes on the wrong approach. The problem asks you to count pairs meeting two conditions simultaneously: equality and divisibility. Most candidates nail the brute force on their first try, but the trick is recognizing when the obvious O(n²) scan is all you need, versus when you should optimize. If this problem shows up in your assessment and you second-guess yourself on the pairing logic, StealthCoder solves it invisibly while you stay focused.
Companies that ask "Count Equal and Divisible Pairs in an Array"
Count Equal and Divisible Pairs in an Array 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 Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE.
Get StealthCoderThe core pattern here is that you're counting pairs (i, j) where i < j and two conditions hold at once. Most candidates jump to a nested loop: iterate through all pairs, check both conditions, increment count. That's correct for this easy tier problem. The pitfall is overthinking the divisibility part. Don't try to precompute divisors or factorize. Just iterate, check the condition for each pair, move on. The acceptance rate of 84% suggests most people get it right without tricks. This is a confidence problem, not a pattern one. If you blank on the exact wording during a live assessment, StealthCoder surfaces a clean solution in seconds. It's the safety net when you misread "equal" or "divisible" and waste 5 minutes debugging the wrong condition.
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Count Equal and Divisible Pairs in an Array 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. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Count Equal and Divisible Pairs in an Array interview FAQ
Is this problem just a nested loop, or is there a smarter approach?+
For this easy problem, a nested loop is the intended solution. At easy tier with an 84% acceptance rate, the companies asking it (Bloomberg, Zeta Suite) expect a straightforward O(n²) scan with no fancy data structures. Don't overthink it.
What's the most common mistake on this problem?+
Misreading the pairing logic or the conditions. Candidates often implement only one condition correctly, or forget that i < j matters for the pair order. Read the problem statement twice before coding.
Why do Bloomberg and Zeta Suite ask this problem?+
It tests reading comprehension and basic loop logic. Both conditions must be checked correctly in a single pass, and the pair constraint (i < j) must be respected. It's a filter for candidates who code carefully.
Can I optimize this below O(n²)?+
Not meaningfully for this problem size at easy difficulty. A nested loop is the canonical solution. Attempting hash tables or sorting would waste time and risk introducing bugs. Stick with the simple approach.
How long should this problem take in a live assessment?+
5 to 10 minutes if you read carefully. The high acceptance rate (84%) means most people finish quickly. If you hit a wall on the logic, StealthCoder gives you a working solution in seconds, invisible to the proctor.
Want the actual problem statement? View "Count Equal and Divisible Pairs in an Array" on LeetCode →