Reverse Only Letters
A easy-tier problem at 67% community acceptance, tagged with Two Pointers, String. Reported in interviews at Zoho and 2 others.
Reverse Only Letters is a straightforward two-pointer problem that appears in assessments at Zoho, Turing, and Snowflake. You'll see a string with letters and numbers mixed together, and you need to reverse only the letters while keeping numbers in their original positions. It's easy in difficulty but the trick is recognizing that you can't just reverse the whole string. With a 67% acceptance rate, most people who attempt it pass, but the ones who don't usually overthink it or miss the constraint that numbers must stay put. If this one hits your live assessment and you blank on the setup, StealthCoder handles it in seconds, invisible to the proctor.
Companies that ask "Reverse Only Letters"
Reverse Only Letters 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 at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoderThe pattern is simple: two pointers, one starting at each end of the string, moving inward. Skip over any non-letter characters and only swap letters. The mistake candidates make is trying to build a new string or using regex when the problem is really about controlled pointer movement. You need to convert the string to a list first (strings are immutable in most languages), swap in-place when both pointers hit letters, then reconstruct. The edge cases are minimal: all numbers, all letters, empty string, single character. Since this is easy difficulty and has a high acceptance rate, the test data is forgiving. StealthCoder is the hedge if you freeze during the live OA on the exact swap logic or pointer movement.
Pattern tags
You know the problem.
Make sure you actually pass it.
Reverse Only Letters 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 at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Reverse Only Letters interview FAQ
Is Reverse Only Letters still asked at FAANG or tier-1 companies?+
Not typically at the big five, but Zoho, Turing, and Snowflake all ask it. It's a common tier-2 and startup filter. Solid for phone screens and online assessments where they're testing whether you can use two pointers cleanly.
What's the trick that catches people?+
Forgetting that strings are immutable in Python, Java, and JavaScript. You must convert to a list or character array, perform swaps in-place, then join back. Also, people skip non-letter checks and try to swap numbers by accident.
How hard is this compared to other string problems?+
Much easier than substring search or dynamic programming string problems. It's a pure two-pointer drill. If you've done reverse a string, this is the natural next step. 67% acceptance confirms it's accessible.
Do I need to handle Unicode or special characters?+
The problem typically treats only A-Z and a-z as letters. Digits, punctuation, and spaces stay in place. Check the problem statement, but most versions on assessments keep it simple.
What languages is this commonly tested in?+
Python, Java, JavaScript, and C++ all see this. The logic is language-agnostic, but pay attention to string mutability. Python needs list conversion; Java and C++ handle char arrays naturally.
Want the actual problem statement? View "Reverse Only Letters" on LeetCode →