Find the middle node in one pass, no length counting, no second pass.
Slow 🐢 moves one node at a time, fast 🐇 moves two.
When fast runs out of road, slow is standing on the middle.
Execution
idle
Press Run to begin.
0 / 0
Speed
Java · running line
slow 🐢fast 🐇middle nodenull / end
O(n) time · O(1) space · for even-length lists this convention returns the
second middle — the loop condition fast != null && fast.next != null is why.