From e78a91731a87b80a4972e40b4b2f44c640f8df62 Mon Sep 17 00:00:00 2001
From: Emir Pasic <emirpasic83@gmail.com>
Date: Sun, 5 Mar 2017 23:33:34 +0100
Subject: [PATCH] - Fix doubly linked list's element's prev pointer when
 inserting

---
 lists/doublylinkedlist/doublylinkedlist.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lists/doublylinkedlist/doublylinkedlist.go b/lists/doublylinkedlist/doublylinkedlist.go
index c82575b..bd85b18 100644
--- a/lists/doublylinkedlist/doublylinkedlist.go
+++ b/lists/doublylinkedlist/doublylinkedlist.go
@@ -259,18 +259,22 @@ func (list *List) Insert(index int, values ...interface{}) {
 			if i == 0 {
 				list.first = newElement
 			} else {
+				newElement.prev = beforeElement
 				beforeElement.next = newElement
 			}
 			beforeElement = newElement
 		}
+		oldNextElement.prev = beforeElement
 		beforeElement.next = oldNextElement
 	} else {
 		oldNextElement := beforeElement.next
 		for _, value := range values {
 			newElement := &element{value: value}
+			newElement.prev = beforeElement
 			beforeElement.next = newElement
 			beforeElement = newElement
 		}
+		oldNextElement.prev = beforeElement
 		beforeElement.next = oldNextElement
 	}
 }