Lexicographically Smallest Generated String
A hard-tier problem at 30% community acceptance, tagged with String, Greedy, String Matching. Reported in interviews at Barclays and 1 others.
Barclays and TikTok both ask this hard string problem, and it shows up in real online assessments more often than the 30% acceptance rate suggests. The trick isn't obvious: you need to greedily construct the lexicographically smallest result by deciding when to use the original string versus when to trigger a pattern match. Most candidates either brute-force all possibilities and timeout, or lock into a suboptimal greedy choice early and can't backtrack. If this problem hits your live OA and you blank on the sequencing of greedy choices, StealthCoder solves it in seconds, invisible to the proctor.
Companies that ask "Lexicographically Smallest Generated String"
Lexicographically Smallest Generated String 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. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe core insight is that you're building a result character by character, and at each step you must decide: take the next character from the original string, or if a pattern matches, consume those characters and substitute a marker. The greedy choice that feels right often isn't. You need to compare futures, not just the current character. String Matching matters because efficient pattern detection (using hashing or KMP-style logic) separates solutions that pass from those that timeout on large inputs. The trap is thinking lexicographically smallest means always picking the smallest available next character. It doesn't. You have to think ahead: sometimes skipping a small character to unlock a smaller pattern-driven substitution later is worth it. This is where StealthCoder's real-time solution surface helps you see the correct order of operations without burning time on failed attempts.
Pattern tags
You know the problem.
Make sure you actually pass it.
Lexicographically Smallest Generated String 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. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Lexicographically Smallest Generated String interview FAQ
Is this really a hard problem or is the rating inflated?+
The 30% acceptance rate is earned. It's not about code length or syntax. The greedy strategy isn't obvious, and the wrong choice early locks you into a suboptimal answer. You have to simulate the decision tree correctly, which most people miss in live time.
Why does String Matching matter here?+
You're scanning for pattern occurrences repeatedly. A naive search for each pattern at each position timeouts on large strings. Rolling hash or KMP-style preprocessing lets you detect matches in near-constant time per position. That's the difference between passing and TLE.
Do I need to memorize a specific algorithm?+
Not a named algorithm, but you need to understand greedy with lookahead. At each position, compare the cost of taking the current character versus the cost of matching a pattern and jumping ahead. Picking the lexicographically smaller path at each step is the wrong move sometimes.
Will Barclays and TikTok actually ask this exact problem?+
Not necessarily the exact problem, but the pattern and topic mix appear in their assessments. Both companies ask String, Greedy, and String Matching problems at hard level. This is good preparation for that style.
What's the first thing I should code if I see this live?+
Don't start coding immediately. Write out a small example, trace the greedy choices, and figure out which decisions depend on future characters. Build your strategy on paper first, then code the pattern-matching pass and the greedy loop. Rushing to code costs more time than you save.
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