Monotonic Array
A easy-tier problem at 62% community acceptance, tagged with Array. Reported in interviews at Ozon and 1 others.
Monotonic Array feels like a warmup until you realize it's asked at real companies like Ozon and Yandex. You get an array and need to determine if it's monotonically increasing, decreasing, or neither. The catch is the interview version often hides edge cases in the problem statement or piles on real-time pressure. 60% pass rate means most candidates solve it, but careless ones stumble on boundary conditions or overthink it. If this lands in your assessment and you blank on the approach, StealthCoder runs invisibly and surfaces a working solution in seconds.
Companies that ask "Monotonic Array"
Monotonic 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 an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe problem looks trivial: iterate once, track whether you've seen a dip or a rise, and decide. The real trap is definition ambiguity. Does 'monotonic increasing' mean strictly increasing (no equals) or non-decreasing (equals allowed). Most candidates misread the spec and code the wrong variant. Another common miss: handling single-element or two-element arrays without explicit checks. A solid approach iterates through the array once, flags whether you've encountered a decrease and an increase, then returns true only if you've never seen both. Time is O(n), space is O(1). The solution is so clean that confident candidates often over-engineer it or second-guess the definition. That hesitation is where StealthCoder's instant answer saves you in a live OA.
Pattern tags
You know the problem.
Make sure you actually pass it.
Monotonic 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 an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Monotonic Array interview FAQ
Is Monotonic Array actually asked at big companies?+
Yes. Ozon and Yandex both report it. The 60% acceptance rate suggests it's not a gimme, which means edge cases or unclear specs trip real candidates. Company size doesn't matter here; it's about catching careless logic.
What's the trick I'm missing if I keep failing?+
Edge case handling and definition clarity. Confirm with the interviewer: does monotonic increasing mean no duplicates allowed, or are equal consecutive elements okay. Then handle arrays smaller than two elements explicitly before your main loop.
Can I solve this in a single pass?+
Yes. Track two booleans: has_increase and has_decrease. Iterate once, flag both, return true only if at least one is false. O(n) time, O(1) space. No need for multiple passes or sorting.
How hard is Array as a topic if I struggle here?+
Monotonic Array is EASY rated and foundational. If you're stuck, focus on iterator discipline and boundary logic before moving to harder array problems. This one teaches the basics well.
Should I memorize this or understand the pattern?+
Understand the pattern. The core insight is that a monotonic array has no 'direction reversals'. Once you see that, the code writes itself. Memorizing code leads to panic on variants.
Want the actual problem statement? View "Monotonic Array" on LeetCode →