Add to Array-Form of Integer
A easy-tier problem at 45% community acceptance, tagged with Array, Math. Reported in interviews at Avito and 2 others.
You're given a large integer represented as an array of digits, and you need to add a number to it. The catch: the integer might not fit in a standard data type, which is why it's stored as an array. Avito, Zoho, and ByteDance have all asked this. The problem looks trivial until you realize you need to handle carry logic correctly and return the result as an array. Most candidates stumble on edge cases around final carries and assume their first pass works. If this problem hits your live assessment and you blank on the carry logic, StealthCoder solves it in seconds.
Companies that ask "Add to Array-Form of Integer"
Add to Array-Form of Integer 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 an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoderThe core trick is simulating grade-school addition by iterating backward through the digit array, adding the number's digits one at a time, and propagating carry to the left. The obvious approach fails when candidates ignore that the number to add can be multi-digit, or they forget to handle the final carry if it extends beyond the array length. The algorithm is straightforward: convert the number to its own digit form, reverse-iterate through both, accumulate carry, and append any remaining carry at the end. Since this is marked Easy with a 45% acceptance rate, the difficulty lies in implementation details and edge cases, not algorithmic insight. During the live assessment, you either nail the carry logic or you don't. StealthCoder is your hedge for the one time the pattern escapes you under pressure.
Pattern tags
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Add to Array-Form of Integer 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 an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Add to Array-Form of Integer interview FAQ
Is this problem actually Easy or do most people struggle with it?+
The acceptance rate is 45%, which means half of submissions fail on first try. The core idea is simple, but carry propagation and edge cases trip up candidates who rush. It's rated Easy because the algorithm itself isn't complex, not because it's trivial in practice.
Which companies ask this and how often?+
Avito, Zoho, and ByteDance have reported asking it. It shows up occasionally in screening rounds. It's not a mega-popular problem, but it appears often enough that you can't ignore it if you're targeting these companies.
What's the main trick I need to know?+
The trick is handling carry correctly when iterating backward through the array and the input number simultaneously. Don't forget that if carry remains after you've consumed both the array and the number, you need to prepend it. This is where most solutions break.
Does this problem test Array or Math harder?+
Both equally. You're manipulating an array structure and performing arithmetic logic. Neither topic dominates. Understanding how to iterate and update an array while tracking carry is the core skill being tested.
How does this compare to other number-as-array problems?+
It's a cleaner version of problems like 'Add Two Numbers' but simpler because you're only adding one number to the array, not two arrays together. If you've solved this, similar array-addition problems feel familiar fast.
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