Robot Bounded In Circle
A medium-tier problem at 56% community acceptance, tagged with Math, String, Simulation. Reported in interviews at Chewy and 6 others.
You're looking at a problem that shows up in assessments at Airbnb, Apple, Nvidia, and Goldman Sachs. Robot Bounded In Circle has a 56% acceptance rate, which means half the people who sit down to solve it either miss the pattern or get tripped up by the simulation. The trick isn't in coding a loop correctly. It's recognizing a mathematical property that lets you skip the brute force entirely. If this hits your live OA and you can't see the shortcut, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Robot Bounded In Circle"
Robot Bounded In Circle 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 used it to pass JPMorgan's OA and system design loop.
Get StealthCoderMost candidates simulate the robot moving and turning on a grid, checking if it ever returns to the origin. That works, but you'll waste time writing the full simulation. The real insight is mathematical: if a robot returns to the origin after one cycle of instructions, the instructions are circular. But more subtly, if it returns to the origin after a multiple of one cycle, or if it's facing a different direction after one cycle (and that direction would eventually loop back), the robot is still bounded. The pattern depends on the final direction and position after executing the instructions once. This combines String parsing with directional Math and Simulation observation. It's the kind of problem where you either see the leap or you code through brute force. StealthCoder is your hedge if the pattern doesn't click during the assessment.
Pattern tags
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Make sure you actually pass it.
Robot Bounded In Circle 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 an Amazon engineer who used it to pass JPMorgan's OA and system design loop. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Robot Bounded In Circle interview FAQ
Why is this a medium and not a hard?+
The simulation itself is straightforward: parse commands, update direction and position, check a condition. The difficulty comes from recognizing the mathematical trick that skips the full loop check. Once you see it, implementation is clean. That's why acceptance sits around 56%, not lower.
Do I really need to simulate multiple cycles?+
No. The trick is that one cycle of instructions is enough to determine if the robot is bounded. If it returns to origin or rotates in a way that repeats within four cycles, it's bounded. You don't need to run thousands of steps.
Is this still asked at FAANG companies?+
Yes. It appears in reports from Apple, Nvidia, Airbnb, and Goldman Sachs. It tests both coding ability and pattern recognition. It's a favorite because the brute-force solution works but isn't elegant, and the clever solution is teachable but not obvious.
How does the direction tracking work?+
Track your current direction as a number (0=north, 1=east, 2=south, 3=west). Each 'L' or 'R' command rotates you. Each 'S' moves you in your current direction. After one full instruction set, if direction has rotated or position is origin, boundedness follows a pattern based on the final direction mod 4.
What's the most common wrong approach?+
Simulating 100,000 or more steps to see if the robot returns, then checking if it escapes. It's inefficient and can timeout. The Math topic hints at a shortcut. You need to think about cycles and rotational symmetry, not raw iteration.
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