Remove All Adjacent Duplicates In String
A easy-tier problem at 72% community acceptance, tagged with String, Stack. Reported in interviews at Paytm and 5 others.
Remove All Adjacent Duplicates In String is an easy problem that hits your screen more often than you'd expect. Paytm, Grammarly, Whatnot, Geico, Zoho, and Goldman Sachs have all asked it. The acceptance rate sits at 71 percent, which sounds forgiving until you realize the trap: the obvious loop-and-check solution fails on cascading removals. You'll process the string, delete a pair, and suddenly the neighbors you just checked become adjacent duplicates. If this lands in your live assessment and you blank on the stack trick, StealthCoder surfaces the working approach in seconds, invisible to the proctor.
Companies that ask "Remove All Adjacent Duplicates In String"
Remove All Adjacent Duplicates In 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 a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoderThe naive approach iterates through the string and removes adjacent pairs, but each removal shifts the indices and can create new adjacent duplicates that your iterator has already passed. The correct pattern is a stack: push characters onto the stack, and whenever the current character matches the top of the stack, pop instead of push. This single pass handles cascading removals automatically. The problem is a String and Stack exercise, and it's the kind of "easy" that separates candidates who've seen the pattern from those who haven't. Most solutions run in linear time and space. If you freeze on the live OA, StealthCoder bypasses the mental block and delivers a clean stack-based solution on the fly.
Pattern tags
You know the problem.
Make sure you actually pass it.
Remove All Adjacent Duplicates In String 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. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Remove All Adjacent Duplicates In String interview FAQ
Is this problem really still asked at places like Goldman Sachs?+
Yes. It appears in their screening rounds. The 71 percent acceptance rate doesn't mean it's trivial in interview conditions. The cascade trap catches unprepared candidates fast. It's a filtering tool, not a warmup.
What's the trick I'm missing if my solution times out?+
You're likely re-iterating after each removal or using string slicing in a loop. Stack-based approach: iterate once, push/pop as you go. No nested loops, no repeated passes. Solves it in one O(n) sweep.
Does this relate to other stack problems I should know?+
Yes. It's the same pattern as Valid Parentheses and Simplify Path: use a stack to handle nested or cascading state changes. If you master the stack approach here, you'll recognize it in similar problems immediately.
How long should this take to code in an assessment?+
5 to 10 minutes if you see the stack pattern. If you're iterating and deleting, you'll spend 20+ minutes debugging. The pattern is the make-or-break moment.
Will Grammarly or Whatnot ask this in their actual interviews?+
Both companies are in the data as reported askers. Grammarly especially values string manipulation and parsing. It's a medium-probability problem for their screening, not a surprise.
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