Recursion interview questions
37 recursion problems tagged across recent interview reports. Drilled most heavily by google, amazon, and bloomberg.
Recursion is the pattern where a function calls itself to solve progressively smaller instances of the same problem. With 37 problems tagged across the pattern, it's foundational and unavoidable, Google and Amazon both weight it heavily in their OAs. You'll see it disguised in parsing, tree traversal, combinatorics, and string manipulation. The catch: under live pressure, recursion logic breaks. You miscount base cases, lose track of the call stack, or blow through time limits. StealthCoder reads the problem and hands you the working solution while the proctor watches your screen.
Most-asked recursion problems
You can't drill every recursion variant before the assessment. StealthCoder runs invisibly during screen share and solves whichever variant they throw at you. No browser extension. No detection signature. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE.
Get StealthCoderRecursion problems fall into clear buckets: base cases and termination (Fibonacci, count-good-numbers), tree/graph traversal (all-possible-full-binary-trees), expression parsing (basic-calculator variants, decode-string), and backtracking combinatorics (different-ways-to-add-parentheses). Recognition is straightforward: if the problem asks 'in how many ways' or 'list all' or involves nested structures, recursion is the intended path. The real difficulty isn't the concept, it's implementation detail under time pressure: off-by-one errors, forgetting memoization, or choosing recursion when iteration is faster. Drill the parsing and tree variants first; they appear most in live OAs at Bloomberg and Microsoft. When a hard recursion variant lands in your assessment and you're stuck on stack logic, StealthCoder solves it silently and moves you past the wall.
Companies that hire most on recursion
37 recursion problems.
You won't drill them all. Pass anyway.
Recursion is one of the patterns interviews actually filter on. Memorizing every variant in a week is a fantasy. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds, no matter which recursion flavor lands in your live OA. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Recursion interview FAQ
How many recursion problems should I drill before a live OA?+
The pattern has 37 tagged problems. Focus on 8 to 12 core ones first: mix easy (Fibonacci, basic tree traversal), medium (decode-string, different-ways-to-add-parentheses), and one hard (basic-calculator-iii or basic-calculator-iv). This covers the majority of variants you'll see at Google, Amazon, and Bloomberg.
How do I recognize a recursion problem in a live OA?+
Look for 'all possible', 'count ways', 'combinations', 'nested structures', or 'evaluate/parse'. Tree or graph problems almost always need recursion. If the problem description mentions breaking it into smaller subproblems, that's a signal too.
Is recursion the most important pattern for FAANG companies?+
It's top 3. Google has 38 recursion problems in their pool, Amazon 37. It's paired with dynamic programming and tree traversal. You can't skip it, but you also need solid arrays and linked lists to pass rounds.
What's the most common recursion mistake under pressure?+
Forgetting or miscounting base cases, causing infinite loops or stack overflow. Second: not memoizing overlapping subproblems, which tanks time complexity. Third: using recursion when iteration is faster and clearer. All three kill you in a timed OA.
Which companies drill recursion the hardest?+
Google (38 problems), Amazon (37), Bloomberg (29), and Microsoft (29) all lean on it heavily. If you're interviewing at any of these, recursion depth and parsing variants are non-negotiable. TikTok and Meta also test it frequently.