Minimum Time to Revert Word to Initial State II
A hard-tier problem at 34% community acceptance, tagged with String, Rolling Hash, String Matching. Reported in interviews at Sprinklr and 0 others.
You've seen string matching problems that look straightforward until you realize the naive approach times out. Minimum Time to Revert Word to Initial State II is a 34% acceptance HARD problem that Sprinklr asks. The trick isn't obvious: you need to recognize that brute-force character-by-character deletion fails under time pressure, and rolling hash is the pattern that separates clean solutions from TLE. If you blank on the hash optimization during your live OA, StealthCoder runs invisibly and surfaces the working approach in seconds, letting you move on without the panic.
Companies that ask "Minimum Time to Revert Word to Initial State II"
Minimum Time to Revert Word to Initial State II 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 problem tempts you to simulate each deletion step or use string matching naively, both of which fail. The real insight is that you need to find the shortest repeating unit in the string efficiently, and rolling hash (or Z-algorithm) lets you do that in linear time instead of quadratic. Most candidates waste 20 minutes trying direct substring comparisons before recognizing the pattern. The hash function approach avoids constant re-computation of prefix/suffix matches. This is a 'seeing the trick matters' problem, not an implementation grind. Sprinklr specifically hired people who recognize when hashing solves string matching at scale. StealthCoder is your hedge if the pattern doesn't click under live pressure.
Pattern tags
You know the problem.
Make sure you actually pass it.
Minimum Time to Revert Word to Initial State II 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. 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.
Minimum Time to Revert Word to Initial State II interview FAQ
Is this really a hard problem or does it feel harder because of the time limit?+
Both. The algorithmic insight (rolling hash or Z-algorithm for cycle detection) isn't trivial, and a 34% acceptance rate confirms most candidates don't see it fast enough. Under 90 minutes with one shot, it's genuinely hard. Simulation looks tempting but breaks on larger strings.
What's the difference between rolling hash and naive string matching here?+
Naive matching rebuilds substring hashes on every iteration, giving O(n^2) or worse. Rolling hash computes a fingerprint for each prefix and suffix in one pass, then compares hashes in O(1), totaling O(n) with one hash function call per position.
Do I need to implement a custom hash function or can I use a library?+
Most solutions implement rolling hash from scratch to avoid collisions and show algorithmic depth. Python's built-in hash or string methods won't be recognized as solving the core insight. Sprinklr expects you to understand the hash mechanics, not just call a library function.
How does this relate to KMP or Z-algorithm?+
All three solve the same family: find patterns or cycles in strings without quadratic re-scanning. Z-algorithm builds a failure function; rolling hash lets you compare candidate positions instantly. Both O(n), different approaches. Pick whichever you've practiced; both work.
Is this still being asked at Sprinklr or is it dated?+
Sprinklr is listed as having asked this problem. Companies that interview string and hash patterns don't retire them fast. If you're interviewing there soon, assume it's still in rotation. The 34% pass rate suggests it hasn't gotten easier.
Want the actual problem statement? View "Minimum Time to Revert Word to Initial State II" on LeetCode →