int BreadthFirstSearch(List<NodeType> &startstatelist, BinaryTree_AVL<DataType> &startlist, BinaryTree_AVL<DataType> &otherlist) { int status; // track all states created BinaryTree_AVL<String> allstates; // create open priority queue List<Proxy<NodeType> > openpq; // copy list of start states int nodedepth = 1; ListIterator<NodeType> startstateIter(startstatelist); for ( ; !startstateIter.done(); startstateIter++) { // copy start state Proxy<NodeType> pstart(startstateIter()); // set start node depth pstart->setDepth(nodedepth); // insert start state into open queue if ((status = openpq.insertAtEnd(pstart)) != OK) { ERRORD("insertAtFront() failed.", status, errno); return(status); } } // start search loop for (Proxy<NodeType> pnode; ! openpq.isEmpty(); ) { // remove next node from priority open queue if ((status = openpq.removeAtFront(pnode)) != OK) { ERRORD("removeAtFront() failed.", status, errno); return(status); } // set current node depth nodedepth = pnode->getDepth(); // check if we have a goal node or not status = pnode->isGoal(startlist, otherlist); switch (status) { case OK: break; case NOMATCH: case MAXDEPTHEXCEEDED: // no clauses were generated. skip further // processing of this node. continue; case VALID: // goal node, print solution PrintSolution(pnode); PrintRenameVariables(pnode); // check if more than one solutions is required solutionsfound += 1; statistics[SolutionsFound] += 1; totalstatistics[TotalSolutionsFound] += 1; if (solutionsfound >= solutionsrequired) return(VALID); continue; case MAXCLAUSEEXCEEDED: // check if any solutions were found if (solutionsfound > 0) return(VALID); else return(NOTPROVEN); default: // some type of error ERRORD("isGoal() failed.", status, errno); return(status); } // generate the children of the current node if ((status = pnode->expand(startlist, otherlist)) != OK) { ERRORD("expand() failed.", status, errno); return(status); } // set up links to parent and calculate the heuristic value ListIterator<Proxy<NodeType> > childrenIter(*pnode->getChildren()); for ( ; !childrenIter.done(); childrenIter++) { // pointer to child Proxy<NodeType> pchild(childrenIter()); // set up link to parent if (reporttype == ReportParent || reporttype == ReportBoth) pchild->setParent(pnode); // insert into queue if (!bfswithchecks) { pchild->setDepth(nodedepth+1); if ((status = openpq.insertAtEnd( pchild)) != OK) { ERRORD("insertAtEnd() failed.", status, errno); return(status); } } else { statistics[RedundantClauseTestsAttempted] += 1; totalstatistics[TotalRedundantClauseTestsAttempted] += 1; String newnode(pchild->getNormalizedClauses()); if (allstates.retrieve(newnode) == NOMATCH) { pchild->setDepth(nodedepth+1); if ((status = openpq.insertAtEnd( pchild)) != OK) { ERRORD("insertAtEnd() failed.", status, errno); return(status); } } else { statistics[RedundantClausesRejected] += 1; totalstatistics[TotalRedundantClausesRejected] += 1; } } } if (bfswithchecks) { if (allstates.insert(pnode->getNormalizedClauses()) != OK) { ERRORD("insert() failed.", status, errno); return(status); } } } // check if any solutions were found if (solutionsfound > 0) return(VALID); else return(NOTPROVEN); }
int updatepath(int &nodedepth, int &olddepth, Proxy<NodeType> &pnode, List<Proxy<NodeType> > ¤tpath) { int status; // get new node depth nodedepth = pnode->getDepth(); // update path if reporting is on if (reporttype != ReportStack && reporttype != ReportBoth) return(OK); // update path in stack if (currentpath.isEmpty()) { if ((status = currentpath.insertAtFront(pnode)) != OK) { ERRORD("insertAtFront() failed.", status, errno); return(status); } olddepth = nodedepth; } else if (nodedepth <= olddepth) { int nodestopop = olddepth - nodedepth + 1; for (int inode = 1; inode <= nodestopop; inode++) { Proxy<NodeType> ppathnode; if ((status = currentpath.removeAtFront( ppathnode)) != OK) { ERRORD("removeAtFront() failed.", status, errno); return(status); } } if ((status = currentpath.insertAtFront(pnode)) != OK) { ERRORD("insertAtFront() failed.", status, errno); return(status); } olddepth = nodedepth; } else if (nodedepth > olddepth) { if ((status = currentpath.insertAtFront(pnode)) != OK) { ERRORD("insertAtFront() failed.", status, errno); return(status); } olddepth = nodedepth; } else { MustBeTrue(0); } // all done return(OK); }