From f55c76d0fb82c94eb996ddfc41a0758d11cb331b Mon Sep 17 00:00:00 2001
From: Samrat De <rajmalhotra2016iitjee@gmail.com>
Date: Thu, 21 May 2020 17:32:51 +0530
Subject: [PATCH] fix: Doubly Linked List algorithm bug

---
 data_structure/Doubly Linked List.cpp | 34 +++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/data_structure/Doubly Linked List.cpp b/data_structure/Doubly Linked List.cpp
index 84a239d3f..a1b6da3ad 100644
--- a/data_structure/Doubly Linked List.cpp	
+++ b/data_structure/Doubly Linked List.cpp	
@@ -38,13 +38,37 @@ void insert(int x)
 void remove(int x)
 {
 	node *t = start;
-	while (t->val != x)
+	while (t != NULL && t->val != x)
 	{
-		t = t->next;
+		t = t-> next;
 	}
-	t->prev->next = t->next;
-	t->next->prev = t->prev;
-	delete t;
+	if (t == NULL)
+	{
+		return;
+	}
+	// if first element is removed
+	if (t->prev == NULL)
+	{
+		if (t->next == NULL)
+		{
+			start = NULL;
+		}
+		else
+		{
+			start = t->next;
+			start->prev = NULL;
+		}
+	}
+	else if (t->next == NULL)
+	{
+		t->prev->next = NULL;
+	}
+	else
+	{
+		t->prev->next = t->next;
+		t->next->prev = t->prev;
+	}
+	delete t;	
 }
 
 void search(int x)