Transpose Matrix
A easy-tier problem at 74% community acceptance, tagged with Array, Matrix, Simulation. Reported in interviews at ConsultAdd and 1 others.
Transpose Matrix is one of those problems that sounds trivial until you realize your first instinct leaves memory on the table. You're given an m×n matrix and need to return its transpose, which means swapping rows and columns. It hits the easy bucket with a 74% acceptance rate, but that number drops fast if you don't think about in-place operations or rectangular matrices. ConsultAdd and Verkada both ask it. The trap: assuming the input is always square, or building a full copy when constraints allow better. If this lands in your assessment and you blank on the edge cases, StealthCoder surfaces a working solution invisible to the proctor.
Companies that ask "Transpose Matrix"
Transpose Matrix 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 straightforward approach is to create a new n×m matrix and iterate through the original, placing element at [i][j] into position [j][i]. This works and passes, but costs O(m×n) space. The gotcha is handling non-square matrices correctly. If you're asked to do it in-place, you can't actually transpose a rectangular matrix without extra space (you'd need to rearrange in cycles, which gets complex). Most solutions just build the transposed matrix cleanly. The real interview win is showing you thought about the dimensions upfront and didn't hardcode assumptions. Common pitfall: looping from 0 to m and 0 to n on the new matrix instead of 0 to n and 0 to m. StealthCoder handles the iteration order and boundary logic instantly if you hit a wall during the live assessment.
Pattern tags
You know the problem.
Make sure you actually pass it.
Transpose Matrix 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 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.
Transpose Matrix interview FAQ
Is this still asked at real companies?+
Yes. ConsultAdd and Verkada both report it in their hiring loops. It's a screening problem, not a final-round question. You'll see it early because it's fast to code and separates people who think about edge cases from those who don't.
What's the trick that makes people fail?+
Forgetting that the output matrix is n×m, not m×n. Or hardcoding a loop that assumes the matrix is square. Also, some candidates confuse in-place transposition (theoretically possible but complex) with standard transposition (build a new matrix). Stick with the standard approach unless explicitly told to save space.
How does this relate to the Array and Matrix topics?+
It's pure 2D array indexing. You're practicing dimension flipping and nested loops. Simulation is here because you're literally walking through the matrix and writing to a new one. No algorithms, no data structures. Just correct index mapping.
Can you do this in-place without extra space?+
For a square matrix, yes, using cycle-following. For rectangular matrices, no. The interview won't ask for in-place on a rect matrix unless explicitly stated. If they do, clarify first. Most online assessments expect the straightforward O(m×n) space solution.
What languages is this easiest in?+
Python and Java. Python has one-liners with list comprehension or zip(). Java requires nested loops but is clear. C++ works fine too. The logic doesn't change; you're just swapping indices. Language doesn't matter here, execution does.
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