Update AStarSearch.java

Author: bhoomika1714

src/main/java/com/thealgorithms/graph/AStarSearch.java

@@ -2,6 +2,15 @@
 
 import java.util.*;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.PriorityQueue;
+import java.util.Set;
+
 /**
  * A* Search Algorithm for shortest pathfinding.
  *