public void printProofTree(Clause finalClause, LinkedList<Clause> clauseList) {
PriorityQueue<Integer> proofTree =
new PriorityQueue<
Integer>(); // Will be used to order the ancestors of the finalClause for output
LinkedList<Clause> treeQueue =
new LinkedList<
Clause>(); // Will take in the ancestors of the finalClause. Dequeue each element, add
// it to the proofTree, then add the parents to the queue
int[] parentIDs;
treeQueue.add(finalClause);
while (!treeQueue.isEmpty()) {
Clause polledClause = treeQueue.poll();
if (proofTree.contains(
polledClause
.getClauseID())) // Skip this iteration if the clause has already been added to the
// proofTree
{
continue;
}
proofTree.add(polledClause.getClauseID());
parentIDs = polledClause.getParentIDs();
if (parentIDs[0]
!= -1) // if one parent exists, the other must exist and we add the parents to the queue
{
treeQueue.add(clauseList.get(parentIDs[0] - 1)); // add the first parent to the queue
treeQueue.add(clauseList.get(parentIDs[1] - 1)); // add the second parent to the queue
}
}
// output all the clauses in the proof tree
while (proofTree.peek() != null) {
clauseList.get(proofTree.poll() - 1).outputClause();
}
}
public boolean resolve(LinkedList<Clause> clauses) {
// Storing onto the stack to verify clauses in reverse order
// LinkedList<Clause> expansionStack = new LinkedList<Clause>();
PriorityQueue<Clause> expansionQueue =
new PriorityQueue<Clause>(10000, new ClauseSizeComparator());
for (int count = 0; count < clauses.size(); count++) {
expansionQueue.add(clauses.get(count));
}
while (!expansionQueue.isEmpty()) // Until the stack is empty
{
Clause lastClause = expansionQueue.poll();
for (int clauseCount = 0; clauseCount < lastClause.getClauseID() - 1; clauseCount++) {
// If any new clauses are added since last execution
// if(!clauses.getLast().equals(lastClause))
{
// break;
}
Clause tempClause = clauses.get(clauseCount);
int numClausesBeforeExpansion = clauses.size();
boolean result = lastClause.resolution(tempClause, clauses);
if (!result) {
return false;
}
int numClausesAfterExpansion = clauses.size();
// System.out.println(numClausesAfterExpansion - numClausesBeforeExpansion); //Size does not
// change
// If new clauses are added, expand the newly added clause before expanding any other clause
if (numClausesAfterExpansion - numClausesBeforeExpansion > 0) {
expansionQueue.add(clauses.getLast());
}
}
}
return true;
}