Update AttackingPairsHeuristic.java

return type of getNumberOfAttackingPairs() is int. Ideally, return type of h() should be int

Author: Kmayankkr

aima-core/src/main/java/aima/core/environment/nqueens/AttackingPairsHeuristic.java

@@ -10,8 +10,8 @@
  */
 public class AttackingPairsHeuristic implements HeuristicFunction {
 
-	public double h(Object state) {
+	public int h(Object state) {
 		NQueensBoard board = (NQueensBoard) state;
 		return board.getNumberOfAttackingPairs();
 	}
-}
+}