Count the Digits That Divide a Number
A easy-tier problem at 86% community acceptance, tagged with Math. Reported in interviews at tcs and 0 others.
You're looking at a problem that shows up in TCS assessments and reads deceptively simple: count how many digits in a number divide that number evenly. The acceptance rate is 85%, which means most people who attempt it pass, but that's because it's genuinely straightforward once you see the pattern. The trick isn't algorithmic complexity; it's handling edge cases cleanly and not overthinking a problem that's actually about basic iteration and modulo arithmetic. If you blank on the implementation during a live OA, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Count the Digits That Divide a Number"
Count the Digits That Divide a Number 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 who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoderThe core pattern is straightforward: extract each digit, check if the original number is divisible by that digit (remainder is zero), and count the hits. The main pitfalls are forgetting to exclude zero (you can't divide by zero), mishandling single-digit numbers, and off-by-one errors in the loop. The 'obvious' approach of converting to a string, iterating through characters, converting back to integers, and checking divisibility works fine here. There's no hidden optimization or clever math trick; execution clarity matters more. In a live OA, this is where you build confidence with a clean, readable solution. StealthCoder is your hedge if you misread the problem or second-guess yourself on the zero case.
Pattern tags
You know the problem.
Make sure you actually pass it.
Count the Digits That Divide a Number 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 who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Count the Digits That Divide a Number interview FAQ
Is this problem actually asked at TCS, or is that just data noise?+
TCS is in the confirmed list. It's a real ask. The problem is popular in campus placement rounds where they filter for basic coding hygiene. It's not a trick question; they're checking if you can code cleanly under pressure.
What's the trap that makes people fail this despite the high acceptance rate?+
Division by zero. If your number contains a 0 digit, you have to skip it. Second trap: assuming the number is always positive. Check your input constraints. Third: submitting without handling single-digit edge cases.
Do I need to optimize for very large numbers?+
Unlikely given this is tagged Easy and the acceptance rate is high. A straightforward O(d) solution where d is the number of digits will pass. Don't write a fancy approach; correctness and clarity beat micro-optimizations here.
How does this relate to the Math topic?+
It's number theory at the surface level: divisibility and modulo. The math is grade-school. The problem is testing your ability to extract digits and apply a simple predicate, not advanced number theory.
Should I convert to a string or extract digits mathematically?+
Either works. String conversion is cleaner and less error-prone. Extract via modulo and division if you prefer pure math. Both are O(d) and acceptable. Pick the one you write faster without mistakes.
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