question: get the n'th document id from the inverted list . concode_field_sep int ctf concode_elem_sep int tf concode_elem_sep String field concode_elem_sep Vector<DocPosting> postings concode_elem_sep Vector<Integer> positions concode_elem_sep int df concode_elem_sep int docid concode_field_sep boolean appendPosting concode_elem_sep void print concode_elem_sep int getTf
target: int function ( int arg0 ) { return this . postings . get ( arg0 ) . arg0 ; }