Shortest and Lexicographically Smallest Beautiful String
A medium-tier problem at 40% community acceptance, tagged with String, Sliding Window. Reported in interviews at Wells Fargo and 2 others.
You'll hit this problem cold at Wells Fargo, Yelp, or IBM and freeze on what makes a string 'beautiful'. The acceptance rate sits at 40 percent, which means most candidates either overthink the constraint or miss the sliding window entirely. This one punishes you for guessing. The trick isn't the string manipulation itself. It's understanding what 'beautiful' actually means, then realizing you need to apply a two-pointer or sliding window approach to find the shortest valid substring. If you blank on the pattern during your live OA, StealthCoder solves it invisibly while you're screen sharing.
Companies that ask "Shortest and Lexicographically Smallest Beautiful String"
Shortest and Lexicographically Smallest Beautiful 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. Built by an Amazon engineer who realized the OA tests how well you memorized 200 problems, not how well you code.
Get StealthCoderThe problem chains two competing goals: shortest length and lexicographically smallest. Most candidates try brute force substring checks, which tanks at scale. The real insight is that the 'beautiful' constraint is structural, not value-based, so you can slide a window across the string and track whether the current window satisfies the beauty rule. Once you lock the window bounds, you've found a candidate answer. The trick is that multiple valid windows exist, and you have to return the one that's both shortest and lexicographically smallest. Common miss: candidates find any valid substring and stop. Correct approach: enumerate all valid substrings of minimum length, then pick the lexicographically smallest one. Sliding Window from the topics list is your red flag that a two-pointer traversal beats brute force. If this problem lands in your assessment and you haven't drilled the pattern, StealthCoder is your fallback.
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Shortest and Lexicographically Smallest Beautiful String recycles across companies for a reason. It's medium-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 Amazon engineer who realized the OA tests how well you memorized 200 problems, not how well you code. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Shortest and Lexicographically Smallest Beautiful String interview FAQ
What does 'beautiful' mean in this problem?+
The input defines it. Read the problem statement carefully. Beautiful strings have a specific constraint on character patterns or frequencies. The pattern is usually about pairs or alternation. Once you know the rule, sliding window becomes obvious.
Is this still asked at big tech companies?+
Wells Fargo, Yelp, and IBM have all reported it. It's not a FAANG staple, but medium-tier companies and finance platforms use it. Acceptance rate is 40 percent, so it's neither trivial nor rare.
Why doesn't brute force work?+
Brute force checks every substring and validates each one. With a string of length 1000, that's O(n squared) substrings and O(n) validation per substring. Sliding window reduces it to O(n) by expanding and contracting in a single pass.
How do sliding window and lexicographically smallest work together?+
First, use sliding window to find all substrings of minimum length that are beautiful. Then iterate through those candidates and return the one that's lexicographically smallest. Two loops, but the first is O(n) and the second only loops through valid candidates.
What's the most common mistake?+
Candidates find one valid beautiful substring and return it without checking if a shorter or lexicographically smaller one exists. The 'and' in the problem title matters. Both constraints are binding.
Want the actual problem statement? View "Shortest and Lexicographically Smallest Beautiful String" on LeetCode →