Create linked_list_II.py

linked_lists/linked_list_II.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+class Node:
+    
+    def __init__(self, val):
+        
+        self.val = val
+        self.next = None
+
+class LinkedList:
+
+    def __init__(self):
+        
+        self.head = Node(0)
+        self.len = 0
+        
+    def _loop(self , index):
+        
+        node = self.head
+        p = 0
+        while p < index + 1:
+            node = node.next
+            p += 1
+        
+        return node
+        
+    def get(self, index: int) -> int:
+        if self.len <= index or index < 0:
+            return -1
+        
+        node = self._loop(index)
+        
+        return node.val
+
+    def addAtHead(self, val: int) -> None:
+        
+        self.addAtIndex(0, val)
+
+
+    def addAtTail(self, val: int) -> None:
+        
+        self.addAtIndex(self.len, val)
+        
+
+    def addAtIndex(self, index: int, val: int) -> None:
+        
+        if self.len < index:
+            return -1
+
+        if index < 0:
+            index = 0
+        
+        self.len += 1
+
+        node = self.head
+        for _ in range(index):
+            node = node.next
+    
+        new_node = Node(val)
+        new_node.next = node.next
+        node.next = new_node
+
+    def deleteAtIndex(self, index: int) -> None:
+        
+        if self.len <= index or index < 0:
+            return -1
+        
+        self.len -= 1
+
+        node = self.head
+        for _ in range(index):
+            node = node.next
+            
+        node.next = node.next.next
+        
+