<http://webisa.webdatacommons.org/168666997> <http://www.w3.org/ns/prov#wasQuotedFrom> <stackoverflow.com> . <http://webisa.webdatacommons.org/prov/516234944> <http://www.w3.org/ns/prov#wasDerivedFrom> <http://webisa.webdatacommons.org/168666997> . <http://webisa.webdatacommons.org/168666997> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/prov#Entity> . <http://webisa.webdatacommons.org/168666997> <http://www.w3.org/ns/prov#value> "// T is a tree node, H is a hash set, and first is a boolean flag" .