Find the K-Beauty of a Number
A easy-tier problem at 62% community acceptance, tagged with Math, String, Sliding Window. Reported in interviews at Postmates and 1 others.
Find the K-Beauty of a Number is an easy problem that appears in assessments at Postmates and Quora. It's a string manipulation and sliding window problem disguised as math. The acceptance rate sits around 62%, which tells you it's not a trap, but plenty of candidates still misread what the problem is actually asking. You get the problem statement, read it once, and think you understand. Then you code the wrong thing. This is where a quick sanity check matters before you ship code to the grader.
Companies that ask "Find the K-Beauty of a Number"
Find the K-Beauty of 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 trick here is recognizing this isn't really a math problem, it's a string-sliding-window problem. Convert the number to a string, grab every consecutive K-digit substring, and count how many of those substrings divide the original number evenly. The sliding window moves one position at a time. The catch: you need to handle leading zeros in your substrings. Some candidates skip that check and fail edge cases silently. The obvious approach works fine, but the real hurdle is reading the problem statement carefully the first time. If you're staring at this live during an assessment and the definition of K-Beauty isn't clicking, StealthCoder surfaces the exact pattern in seconds while you stay invisible to the proctor.
Pattern tags
You know the problem.
Make sure you actually pass it.
Find the K-Beauty of 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.
Find the K-Beauty of a Number interview FAQ
Is this really an easy problem or just labeled that way?+
It's genuinely easy once you see the pattern. The 62% acceptance rate reflects poor reading, not algorithmic depth. Most candidates who code it correctly on the first shot say it felt trivial. The speed of implementation matters more than the complexity.
Do I need to convert the number to a string?+
Yes. Extracting K consecutive digits cleanly is much simpler as a string slice than doing modulo arithmetic. Convert, iterate with a sliding window, extract each substring, convert back to int, and check divisibility.
What kills candidates on this problem?+
Misreading the definition of K-Beauty. Some rush and think you count digit occurrences, or you sum digits, or you check divisibility of K alone. Re-read the actual definition twice before coding. Second mistake: not handling leading zeros in substrings, which break integer conversion silently.
How does the sliding window apply here?+
You maintain a fixed-size window of K characters and slide it one position at a time across the string representation of the number. Each window gives you one K-digit substring to test for divisibility. Classic O(n) approach where n is the digit count.
Is this problem still asked at Postmates and Quora?+
Both companies have reportedly asked it. It's a low-friction assessment problem: runs fast, easy to grade, and filters out candidates who skip careful reading. Expect to see it in their screening rounds.
Want the actual problem statement? View "Find the K-Beauty of a Number" on LeetCode →