remove middle points in line segments: comments + test case added

Author: Ram swaroop

src/me/ramswaroop/linkedlists/RemoveMiddlePointsFromLineSegments.java

@@ -12,6 +12,23 @@
  */
 public class RemoveMiddlePointsFromLineSegments {
 
+    /**
+     * Given a linked list of co-ordinates representing line segments, we have
+     * to remove those nodes which represent the middle points.
+     * <p/>
+     * Example:
+     * Input:
+     * (0,10)-> (1,10)-> (3,10)-> (10,10)-> (10,8)-> (10,5)-> (20,5)-> (40,5)
+     * Output:
+     * (0,10)-> (10,10)-> (10,5)-> (40,5)
+     * <p/>
+     * Input:
+     * (2,3)->(4,3)->(6,3)->(10,3)->(12,3)
+     * Output:
+     * (2,3)->(12,3)
+     *
+     * @param node
+     */
     public static void removeMiddlePointsFromLineSegments(SingleLinkedNode<Point> node) {
 
         SingleLinkedNode<Point> curr1 = node, curr2 = node;
@@ -29,13 +46,15 @@ public static void removeMiddlePointsFromLineSegments(SingleLinkedNode<Point> no
                 }
                 curr1.next = curr2;
             } else {
+                System.out.println("Linked list doesn't represent line segments!");
                 return;
             }
             curr1 = curr1.next;
         }
     }
 
     public static void main(String a[]) {
+        // test case 1
         SingleLinkedList<Point> linkedList = new SingleLinkedList<>();
         linkedList.add(new Point(0, 10));
         linkedList.add(new Point(1, 10));
@@ -48,6 +67,17 @@ public static void main(String a[]) {
         linkedList.printList();
         removeMiddlePointsFromLineSegments(linkedList.head);
         linkedList.printList();
+
+        // test case 2
+        SingleLinkedList<Point> linkedList2 = new SingleLinkedList<>();
+        linkedList2.add(new Point(2, 3));
+        linkedList2.add(new Point(4, 3));
+        linkedList2.add(new Point(6, 3));
+        linkedList2.add(new Point(10, 3));
+        linkedList2.add(new Point(12, 3));
+        linkedList2.printList();
+        removeMiddlePointsFromLineSegments(linkedList2.head);
+        linkedList2.printList();
     }
 }