~/boss / loop-demon
Floyd's cycle detection
The Loop Demon
Two heroes, no map. Find the room where the loop begins.
Loading the fight…
How to beat it
The turtle walks one room per step and the rabbit runs two. In a loop, the rabbit always laps the turtle. Then send the turtle back to the entrance and walk them both one room at a time.
Now the real boss
Interviews ask for the code. Watch it run, then write it yourself, tested in Python, C++ or Java.
On your phone? Writing code is easier on a laptop: open bossfight.dev/problems/linked-list-cycle-ii there. Sign in with GitHub to keep your progress on every device.