Permutations
A medium-tier problem at 81% community acceptance, tagged with Array, Backtracking. Reported in interviews at Workday and 25 others.
Permutations is a medium-difficulty backtracking problem that appears across 26+ companies, including Workday, TikTok, Microsoft, and Citadel. You're given an array of distinct integers and need to return all possible orderings. The acceptance rate sits at 80%, but that number masks a real gap: candidates who've drilled backtracking patterns solve it in minutes, and those who haven't often freeze mid-OA. If you hit this problem live and blank on the recursion structure, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Permutations"
Permutations 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 a senior engineer who knows the OA is theater. This is the script.
Get StealthCoderThe trap is thinking you need to pre-generate or shuffle the input. The pattern is pure backtracking: pick an unused element, recurse on the remaining set, backtrack and try the next candidate. Most candidates start strong but fumble the base case or the swap-restore logic. The trick is maintaining state cleanly, either by tracking which indices you've used or by swapping in-place and undoing it. This problem is a gateway to harder combinatorial problems. Array and Backtracking are the listed topics, and both are essential here. The backtracking pattern you nail on Permutations transfers directly to N-Queens, Sudoku, and constraint-satisfaction problems you'll see at these companies. If the recursion tree doesn't feel natural, StealthCoder is your hedge for the live assessment when time pressure hits.
Pattern tags
You know the problem.
Make sure you actually pass it.
Permutations 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 a senior engineer who knows the OA is theater. This is the script. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Permutations interview FAQ
Is Permutations actually asked at top companies or just in prep platforms?+
Yes. It's reported by 26+ companies including Microsoft, LinkedIn, Citadel, and Booking.com. It's a canonical backtracking problem, not a rarity. Expect it in take-home OAs and live coding rounds. The 80% acceptance rate reflects that it's standard, not that it's trivial.
What's the core trick if I don't remember the pattern?+
Backtracking with state management. Pick an element, recurse on what's left, undo your choice, repeat. The key is the 'undo' step. Most failures come from forgetting to restore state before trying the next branch. Your base case is when you've used all elements.
How does Permutations relate to Array problems I've already seen?+
Permutations uses arrays as input but is fundamentally a backtracking pattern, not an array-manipulation trick. You're exploring search trees, not optimizing indexing or pointers. If you're weak on backtracking, this exposes it fast. If you're strong, it's a confidence builder before harder constraint problems.
Should I memorize the solution or understand the recursion?+
Understand the recursion. The pattern is straightforward once it clicks: choose, recurse, unchoose. Memorizing a specific code snippet will fail you if the interviewer tweaks the problem to ask for combinations, permutations of length k, or unique permutations with duplicates.
What happens if I blank on the backtracking structure during the OA?+
That's when you need a safety net. If you've drilled it, muscle memory carries you. If you haven't, time pressure makes it worse. StealthCoder sits invisibly during your screen share and can surface a working solution so you move past this blocker and show competence on the rest of your assessment.
Want the actual problem statement? View "Permutations" on LeetCode →