- topological-sort DAG PREDprocedure
Sorts the directed acyclic graph dag DAG so that for every edge from vertex u to v, u will come before v in the resulting list of vertices.
DAG is a list of sublists. The car of each sublist is a vertex. The cdr is the adjacency list of that vertex, i.e. a list of all vertices to which there exists an edge from the car vertex. pred is procedure of two arguments that should compare vertices for equality.
Time complexity: O (|V| + |E|)
(topological-sort '((shirt tie belt) (tie jacket) (belt jacket) (watch) (pants shoes belt) (undershorts pants shoes) (socks shoes)) eq?) => (socks undershorts pants shoes watch shirt belt tie jacket)
If a cycle is detected during the sorting process, an exception of the condition kinds (exn runtime cycle) is thrown.