Number of Subarrays with Bounded Maximum
A medium-tier problem at 54% community acceptance, tagged with Array, Two Pointers. Reported in interviews at Quora and 0 others.
You need to count subarrays where every element falls within a given range [left, right]. Quora has asked this. It looks straightforward until you realize the brute force solution is too slow, and the obvious greedy approach won't track the valid window correctly. The trick is a mathematical one: instead of counting subarrays directly, you count by subtraction. If you've never seen this pattern, you'll stall during the live assessment. StealthCoder surfaces the working solution in seconds if you blank, invisible to the proctor.
Companies that ask "Number of Subarrays with Bounded Maximum"
Number of Subarrays with Bounded Maximum 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 problem demands you find subarrays where max(subarray) is between left and right inclusive. A nested loop gives you O(n^2) or worse. The real solution uses a two-pointer or sliding-window style count: compute the total subarrays with max less than or equal to right, then subtract subarrays with max less than or equal to left minus one. This flip from 'count valid directly' to 'count via subtraction' is the key insight most candidates miss. Once you see it, implementation is clean. When you hit this live and the obvious path fails, StealthCoder executes the subtraction logic instantly and lets you move forward.
Pattern tags
You know the problem.
Make sure you actually pass it.
Number of Subarrays with Bounded Maximum 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 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.
Number of Subarrays with Bounded Maximum interview FAQ
Is this really a medium, or does it feel harder?+
Acceptance rate sits just above 53%, which means most people who attempt it submit a correct solution. But that includes those who've seen the trick before. If you hit it cold, the insight gap is real. The implementation itself is not complex once you know the pattern.
Why doesn't a sliding window with two pointers work directly?+
A standard sliding window assumes monotonicity: elements entering increase a metric, and shrinking the window decreases it. Here, adding an element can jump the max value, and removing one doesn't guarantee the max shrinks. You can't reliably 'maintain' a window. Subtraction avoids this by counting two simpler problems instead.
What's the relationship between this problem and the Array and Two Pointers topics?+
Two Pointers is listed but in a non-obvious way. You're not sliding a window like classic two-pointer problems. Instead, you're iterating the array once and counting elements in a range. The 'two pointers' framing is loose here. The real skill is the counting trick, not pointer manipulation.
If I haven't seen this before, how do I derive the solution under pressure?+
Think about it differently: instead of 'max in range [left, right]', ask 'how many subarrays have max at most right.' Then ask 'how many have max at most left-1.' Subtract them. This reframe often clicks when the direct count doesn't. It's a common technique in range-count problems.
Will Quora actually ask this exact problem, or a variation?+
Company interview data reflects problems asked historically, but wording and constraints shift. The core pattern is recognizable: you'll see 'count subarrays' with a 'bounded' or 'range' constraint. The subtraction insight applies to many similar problems, so mastering this one arms you for the family.
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