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Simplyfiyng BasicOperations intersection #5

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Simplyfiyng BasicOperations intersection #5

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53 changes: 2 additions & 51 deletions src/dk/brics/automaton/BasicOperations.java
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Original file line number Diff line number Diff line change
Expand Up @@ -276,59 +276,10 @@ static public Automaton minus(Automaton a1, Automaton a2) {
* the languages of the given automata.
* Never modifies the input automata languages.
* <p>
* Complexity: quadratic in number of states.
* Complexity: linear in number of states (if already deterministic).
*/
static public Automaton intersection(Automaton a1, Automaton a2) {
if (a1.isSingleton()) {
if (a2.run(a1.singleton))
return a1.cloneIfRequired();
else
return BasicAutomata.makeEmpty();
}
if (a2.isSingleton()) {
if (a1.run(a2.singleton))
return a2.cloneIfRequired();
else
return BasicAutomata.makeEmpty();
}
if (a1 == a2)
return a1.cloneIfRequired();
Transition[][] transitions1 = Automaton.getSortedTransitions(a1.getStates());
Transition[][] transitions2 = Automaton.getSortedTransitions(a2.getStates());
Automaton c = new Automaton();
LinkedList<StatePair> worklist = new LinkedList<StatePair>();
HashMap<StatePair, StatePair> newstates = new HashMap<StatePair, StatePair>();
StatePair p = new StatePair(c.initial, a1.initial, a2.initial);
worklist.add(p);
newstates.put(p, p);
while (worklist.size() > 0) {
p = worklist.removeFirst();
p.s.accept = p.s1.accept && p.s2.accept;
Transition[] t1 = transitions1[p.s1.number];
Transition[] t2 = transitions2[p.s2.number];
for (int n1 = 0, b2 = 0; n1 < t1.length; n1++) {
while (b2 < t2.length && t2[b2].max < t1[n1].min)
b2++;
for (int n2 = b2; n2 < t2.length && t1[n1].max >= t2[n2].min; n2++)
if (t2[n2].max >= t1[n1].min) {
StatePair q = new StatePair(t1[n1].to, t2[n2].to);
StatePair r = newstates.get(q);
if (r == null) {
q.s = new State();
worklist.add(q);
newstates.put(q, q);
r = q;
}
char min = t1[n1].min > t2[n2].min ? t1[n1].min : t2[n2].min;
char max = t1[n1].max < t2[n2].max ? t1[n1].max : t2[n2].max;
p.s.transitions.add(new Transition(min, max, r.s));
}
}
}
c.deterministic = a1.deterministic && a2.deterministic;
c.removeDeadTransitions();
c.checkMinimizeAlways();
return c;
return union(a1.complement(),a2.complement()).complement();
}

/**
Expand Down