[simonh]

Off the top of my head, because if you don’t know where the last element points back to, and there’s an even chance it could be any previous element, the median element is the one on the middle. Two at a time means when you reach the last element and loop back. The lagging pointer will point to the middle element so. Across a population on lists, it will perform better that ratios that favour the lagging pointer being closer to ge back end of the list when the leading pointer loops.

Also, with a 3 skip you could jump 2 ahead of the lagging pointer when you loop back behind and jump over it, which means when it advances it won’t catch you so they won’t meet.