Linked List Cycle Detection, two ways

Try:
CALL
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Code

The highlighted line runs next. The pill shows the live values in the running call.

Cost

Work done so far, and how the two solutions compare

The list

The arc over the top is the tail's link back into the list

Keyboard: ← → step, Space play or pause. Up to 8 node values; index is where the tail links back (−1 for no cycle). As in the problem, index only builds the list; the solutions never see it.