[pull] master from cheran-senthil:master

README.md

@@ -13,6 +13,7 @@
     <a href="https://github.com/meooow25">meooow</a> &emsp;
     <a href="https://github.com/tfg50">tfg</a> &emsp;
     <a href="https://github.com/sgtlaugh">sgtlaugh</a> &emsp;
+    <a href="https://github.com/abertell">abertell</a> &emsp;
   </strong>
 </div>
 

pyrival/data_structures/LinkedList.py

@@ -84,25 +84,55 @@ def insert(self, index, value):
             self.insert_between(new_node, self.sentinel.prev, self.sentinel)
         else:
             raise IndexError
-        self.__len += 1
 
     def insert_between(self, node, left_node, right_node):
         if node and left_node and right_node:
             node.prev = left_node
             node.next = right_node
             left_node.next = node
             right_node.prev = node
+            self.__len += 1
         else:
             raise IndexError
 
+    def insert_after(self, node, value):
+        new_node = Node(value)
+        node.next.prev = new_node
+        new_node.next = node.next
+        node.next = new_node
+        new_node.prev = node
+        self.__len += 1
+
     def merge_left(self, other):
         self.sentinel.next.prev = other.sentinel.prev
         other.sentinel.prev.next = self.sentinel.next
         self.sentinel.next = other.sentinel.next
         self.sentinel.next.prev = self.sentinel
+        self.__len += other.__len
 
     def merge_right(self, other):
         self.sentinel.prev.next = other.sentinel.next
         other.sentinel.next.prev = self.sentinel.prev
         self.sentinel.prev = other.sentinel.prev
         self.sentinel.prev.next = self.sentinel
+        self.__len += other.__len
+
+    def pop(self, node = None):
+        if node == None:
+            node = self.sentinel.prev
+        if self.__len < 1:
+            raise IndexError
+        node.prev.next = node.next
+        node.next.prev = node.prev
+        self.__len -= 1
+        return node.value
+
+    def before(self, node):
+        if node.prev == self.sentinel:
+            return node.prev.prev
+        return node.prev
+
+    def after(self, node):
+        if node.next == self.sentinel:
+            return node.next.next
+        return node.next