1 files changed, 31 insertions, 25 deletions

diff --git a/src/jrummikub/ai/fdsolver/constraint/IndexConstraint.java b/src/jrummikub/ai/fdsolver/constraint/IndexConstraint.java
index 9d80a37..6698282 100644
--- a/src/jrummikub/ai/fdsolver/constraint/IndexConstraint.java
+++ b/src/jrummikub/ai/fdsolver/constraint/IndexConstraint.java
@@ -8,6 +8,8 @@ import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 
+import org.w3c.dom.ranges.Range;
+
 import jrummikub.ai.fdsolver.Constraint;
 import jrummikub.ai.fdsolver.Propagator;
 import jrummikub.ai.fdsolver.Satisfiability;
@@ -47,16 +49,16 @@ public class IndexConstraint<T> extends Constraint {
 
 		@Override
 		public void propagate() {
-			HashSet<T> union = new HashSet<T>();
+			HashSet<T> invUnion = new HashSet<T>(target.getRange());
 			for (int i : index.getRange()) {
-				union.addAll(list.get(i).getRange());
-			}
-			for (Iterator<T> i = target.iterator(); i.hasNext();) {
-				T val = i.next();
-				if (!union.contains(val)) {
-					i.remove();
+				invUnion.removeAll(list.get(i).getRange());
+				if (invUnion.isEmpty()) {
+					return;
 				}
 			}
+			for (T val : invUnion) {
+				target.invalidate(val);
+			}
 		};
 	}
 
@@ -70,9 +72,8 @@ public class IndexConstraint<T> extends Constraint {
 		public void propagate() {
 			for (Iterator<Integer> i = index.iterator(); i.hasNext();) {
 				int id = i.next();
-				HashSet<T> range = new HashSet<T>(target.getRange());
-				range.retainAll(list.get(id).getRange());
-				if (range.isEmpty()) {
+				Var<T> item = list.get(id);
+				if (Collections.disjoint(item.getRange(), target.getRange())) {
 					i.remove();
 				}
 			}
@@ -107,28 +108,33 @@ public class IndexConstraint<T> extends Constraint {
 		}
 		return Arrays.<Propagator> asList(new UnionProp(), new IndexProp(), new VarProp());
 	}
-
+	
 	@Override
-	public Satisfiability getSatisfiability() {
-		HashSet<T> union = new HashSet<T>();
+	public boolean isSatisfiable() {
 		for (int i : index.getRange()) {
-			union.addAll(list.get(i).getRange());
-		}
-		boolean isSat = false;
-		for (T val : target.getRange()) {
-			if (union.contains(val)) {
-				isSat = true;
-				break;
+			if(!Collections.disjoint(list.get(i).getRange(), target.getRange())) {
+				return true;
 			}
 		}
-		if (!isSat) {
+		return false;
+	}
+
+	@Override
+	public Satisfiability getSatisfiability() {
+		boolean sat = isSatisfiable();
+		if (!sat) {
 			return Satisfiability.UNSAT;
-		} else {
-			if (union.size() == 1 && target.getRange().size() == 1) {
-				return Satisfiability.TAUT;
-			} else {
+		}
+		if (target.getRange().size() > 1)
+			return Satisfiability.SAT;
+		for (int i : index.getRange()) {
+			Var<T> var = list.get(i); 
+			if (var.getRange().size() > 1)
+				return Satisfiability.SAT;
+			if(var.getValue() != target.getValue()) {
 				return Satisfiability.SAT;
 			}
 		}
+		return Satisfiability.TAUT;
 	}
 }