To determine whether there is a cycle in a linked list while using constant memory, have two iterators; one jumping one node per loop and the other jumping 2 nodes per loop, and if the nodes equal eachother before the hare finds some final node, then there exists a loop.
Subset of a weighted graph that is:
Greedy algorithm that forms a MST from a graph \(G\) that works by choosing the closest vertex not yet in the MST