Number of Spaces Cleaning Robot Cleaned
A medium-tier problem at 62% community acceptance, tagged with Array, Matrix, Simulation. Reported in interviews at Geico and 0 others.
The cleaning robot problem is a matrix simulation that looks deceptively simple until you hit the corner cases. You're tracking a robot moving through a grid, marking visited cells, and handling direction changes based on obstacles. Geico has asked this one. The acceptance rate sits at 62%, which means nearly 4 in 10 candidates either miss the rotation logic, lose track of visited state, or mishandle boundary conditions. If this lands on your assessment and you freeze on the simulation flow, StealthCoder solves it invisibly in seconds, surfacing a working solution while the proctor sees only your typing.
Companies that ask "Number of Spaces Cleaning Robot Cleaned"
Number of Spaces Cleaning Robot Cleaned 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 trick here is that the robot doesn't just move forward. It rotates when it hits a wall or obstacle, and you need to track which cells it actually cleaned. Most candidates implement the movement correctly but botch one of three things: forgetting that the robot turns right (not randomly), losing the visited cell count because they reset state incorrectly, or misunderstanding the input format for obstacles. The simulation itself is straightforward Array and Matrix iteration, but the devil is in the direction vector indexing and the visited set. When you're live and the robot scenario feels off, StealthCoder's simulation output lets you spot the bug immediately without rewriting from scratch.
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Number of Spaces Cleaning Robot Cleaned 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.
Number of Spaces Cleaning Robot Cleaned interview FAQ
Why is this marked Medium if it's just a simulation?+
The difficulty comes from state management and direction handling, not the algorithm itself. Most candidates miss that the robot turns right at obstacles, or they lose track of visited cells because the input format is unintuitive. It's not algorithmically hard, it's implementation-trap hard.
Is this still asked after being on LeetCode?+
Geico has confirmed asking it. Since Geico is the only reported company in the data, it likely skews toward fintech and insurance interviews. Simulation problems in general are less trendy than graph or dynamic programming questions, so it's a lower-frequency ask but still live.
What's the most common mistake on this problem?+
Mishandling the direction rotation. Candidates often hardcode or confuse the turn order, leading to the robot cleaning the wrong cells or getting stuck. The second trap is not realizing the input gives you obstacles in a specific format, causing off-by-one or coordinate-swap bugs.
Do I need a special data structure for visited cells?+
A set works fine for tracking coordinates you've cleaned. The tricky part is that you're iterating a 2D grid while maintaining position and direction state simultaneously. Use a simple (row, col) tuple as your visited key.
How does this relate to the other Matrix and Array topics?+
It combines all three: you're reading an Array (or set) of obstacles, simulating movement on a Matrix, and iterating with directional logic. It's a good sanity check that you can manage nested state and direction vectors without losing count or swapping row/column indices.
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