Fill Missing Data
A easy-tier problem at 72% community acceptance, tagged with . Reported in interviews at Acko and 0 others.
Fill Missing Data is showing up in live assessments, and it's the kind of problem that looks trivial until you misread the constraints. It's asked at Acko and has a 72% acceptance rate, which sounds high until you're the one who blanked on edge cases under time pressure. The trap here is assuming the obvious approach works for all input shapes. If you hit this in your OA and freeze on the data structure or iteration logic, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Fill Missing Data"
Fill Missing Data 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. Built by a senior engineer who knows the OA is theater. This is the script.
Get StealthCoderThe core challenge is handling missing or incomplete data across some structure, array, matrix, or nested object. The naive approach often breaks because you're either iterating wrong, mutating while you shouldn't, or not accounting for boundary conditions. The real trick is usually about order of operations: do you fill row by row or column by column? Do you need to preserve original indices? Are nulls and zeros different states? The problem tests whether you read the full spec before coding. Under live assessment pressure, that's where people slip. StealthCoder hedges you here by reading the exact problem statement and surfacing the correct interpretation and implementation before you waste cycles on the wrong approach.
You know the problem.
Make sure you actually pass it.
Fill Missing Data 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. Built by a senior engineer who knows the OA is theater. This is the script. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Fill Missing Data interview FAQ
Is Fill Missing Data actually easy, or is the acceptance rate misleading?+
The 72% rate is genuine easy territory, but the gap between passing and failing often comes down to misreading what 'fill' means in context. Some candidates overthink it. Read the spec word-for-word, especially examples, before you code.
What's the most common mistake people make on this problem?+
Assuming the data structure is uniform when it isn't, or trying to fill in-place when you should create a new structure. The second mistake wastes time backtracking. Clarify your data layout first.
Does Acko ask this as a screening filter or in later rounds?+
No data on where it sits in Acko's funnel. Treat it as a screening problem. An easy rating and high acceptance means you need near-perfect execution to stand out on other dimensions.
Are there any topics or prerequisites I should review before tackling this?+
Input doesn't specify topics, so assume basic array and object iteration. If the problem involves matrices, brush up on row and column traversal patterns. If nested structures, practice careful indexing.
If I blank on this during a live OA, how do I recover without StealthCoder?+
Ask the interviewer to walk through a small example step by step. That forces you to clarify what 'fill' means and often surfaces the approach. Write pseudocode first, trace it, then code.
Want the actual problem statement? View "Fill Missing Data" on LeetCode →