Merge pull request TheAlgorithms#774 from abhijay94/master

yanglbme · web-flow · commit 990b88f72fb1 · 2019-05-30T19:27:51.000+08:00
Fix TheAlgorithms#773 (Deleting an element that doesn't exist causes NPE)
diff --git a/DataStructures/Lists/DoublyLinkedList.java b/DataStructures/Lists/DoublyLinkedList.java
@@ -116,8 +116,13 @@ public Link deleteTail() {
     public void delete(int x) {
         Link current = head;
 
-        while (current.value != x) // Find the position to delete
-            current = current.next;
+        while (current.value != x) {// Find the position to delete
+            if (current != tail) {
+                current = current.next;
+            } else {// If we reach the tail and the element is still not found
+                throw new RuntimeException("The element to be deleted does not exist!");
+            }
+        }
 
         if (current == head)
             deleteHead();
