Update DoublyLinkedList.java

Author: Prashansa-K

com/williamfiset/algorithms/datastructures/linkedlist/DoublyLinkedList.java

@@ -78,37 +78,32 @@ public void addFirst(T elem) {
   }
 
   // Add an element at a specified index
-  public void addAt(int index, T data) throws Exception
-	{
-		if(index<0)
-		{
-			throw new Exception("Illegal Index");
-		}
-		if(index==0)
-		{
-			addFirst(data);
-			return;
-		}
-		
-		if(index==size)
-		{
-			addLast(data);
-			return;
-		}
-		
-		Node<T> temp=head;
-		for(int i=0;i<index-1;i++)
-		{
-			head=head.next;
-		}
-		Node<T> newNode = new Node(data,null,null);
-		newNode.next=head.next;
-		newNode.prev=head.prev;
-		head.next=newNode;
-		head=temp;
-		
-		size++;
-	}
+  public void addAt(int index, T data) throws Exception {
+    if (index < 0) {
+      throw new Exception("Illegal Index");
+    }
+    if (index == 0) {
+      addFirst(data);
+      return;
+    }
+
+    if (index == size) {
+      addLast(data);
+      return;
+    }
+
+    Node<T> temp = head;
+    for (int i = 0; i < index - 1; i++) {
+      temp = temp.next;
+    }
+    Node<T> newNode = new Node(data, null, null);
+    newNode.next = temp.next;
+    newNode.prev = temp.prev;
+    temp.next = newNode;
+
+    size++;
+  }
+	
   // Check the value of the first node if it exists, O(1)
   public T peekFirst() {
     if (isEmpty()) throw new RuntimeException("Empty list");