Create Sorted Array through Instructions
A hard-tier problem at 40% community acceptance, tagged with Array, Binary Search, Divide and Conquer. Reported in interviews at Akuna Capital and 0 others.
You're given a blank array and a list of instructions to build it by inserting numbers at specific positions. The problem sounds deceptively simple until you realize that each insertion shifts indices, and tracking positions becomes a bottleneck. Akuna Capital reports this one. You need to either simulate with a smart data structure or use a divide-and-conquer trick that most people miss in the live OA. It's a 40% acceptance rate for a reason. If you haven't drilled the pattern and hit this during screen share, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Create Sorted Array through Instructions"
Create Sorted Array through Instructions 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 naive approach inserts into an array and shifts elements each time, which explodes to O(n squared). The trick is decoupling the position tracking from the final array shape. You can use a Binary Indexed Tree or Segment Tree to count how many elements were inserted before each position, then work backwards or use merge sort to map logical positions to actual indices. Some candidates catch the ordered set hint and use a balanced BST. The real trap is thinking you have to build the array forward. Stop. Work backwards or count inversions. Most people time out on the simulation path. StealthCoder hedges this by showing the efficient reconstruction pattern when the obvious insertion loop hits its wall.
Pattern tags
You know the problem.
Make sure you actually pass it.
Create Sorted Array through Instructions recycles across companies for a reason. It's hard-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.
Create Sorted Array through Instructions interview FAQ
Is this really a hard problem, or just unfamiliar?+
It's genuinely hard. The 40% acceptance rate reflects that even experienced candidates miss the index-shifting trick in a live setting. The naive approach feels right until it times out. It's not about coding speed, it's about recognizing that direct simulation is the trap.
Do I need to know segment trees to solve this?+
No. Segment trees, Binary Indexed Trees, and ordered sets are all viable. You can also solve it with merge sort and counting. Pick whichever you know best. The key is realizing that forward simulation won't work and that you need to track positions cleverly.
What's the trick I'm missing if I time out?+
You're probably building the array forward with O(n) insertions per instruction. Stop. Either count how many elements end up before each position using a tree, or reconstruct backwards from the instructions. The problem is about smart indexing, not array manipulation.
How does this relate to the other data structure topics listed?+
Array is the output. Binary Search, BST, and tree structures are tools to track positions without naive shifting. Divide and Conquer (merge sort) is one solution path. Pick the approach that fits your toolkit best.
Should I expect this from Akuna Capital?+
Akuna is quant and systems-focused, so yes. They test hard algorithmic problems under time pressure. This fits their signal. Prepare for efficient data structure usage, not just correctness.
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