import java.util.*;
import java.lang.reflect.*;
-class Result implements GraphViz.ToGraphViz {
+final class Result implements GraphViz.ToGraphViz {
private Forest f;
private Node parent;
private GSS.Phase phase;
private Position reduction;
+ private HashSet<Node> children = new HashSet<Node>();
+ private boolean destroyed = false;
+ private int usedByNonDoomedNode = 0;
public Position reduction() { return reduction; }
public GSS.Phase phase() { return phase; }
public Forest getForest() { return f; }
public Node parent() { return parent; }
+ public void addChild(Node child) {
+ children.add(child);
+ usedByNonDoomedNode += child.state().doomed ? 0 : 1;
+ }
+ public void removeChild(Node child) {
+ children.remove(child);
+ usedByNonDoomedNode -= child.state().doomed ? 0 : 1;
+ }
+
+ public boolean usedByAnyNode() { return children.size() > 0; }
+ public boolean usedByNonDoomedNode() { return usedByNonDoomedNode > 0; }
+
+ public String toString() { return super.toString()+"->"+parent(); }
+
+ public void check() { if (children.size()==0) destroy(); }
+ public void destroy() {
+ if (destroyed) return;
+ if (parent==null) return; // never destroy the "primordeal" result
+ destroyed = true;
+ if (parent() != null) {
+ parent().removeChild(this);
+ parent().check();
+ }
+ OUTER: while(true) {
+ for(Node n : children) {
+ children.remove(n);
+ n.removeResult(this);
+ n.check();
+ continue OUTER;
+ }
+ break;
+ }
+ }
public Result(Forest f, Node parent, Position reduction) {
this.f = f;
this.reduction = reduction;
this.parent = parent;
+ if (parent != null) parent.addChild(this);
if (parent != null) phase = parent.phase();
}