insert in linked list

Author: raianmol172

insert_linked_list.py

@@ -0,0 +1,88 @@
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+        self.size = 0
+
+    def get(self, index):
+        if index < 0 or index >= self.size:
+            return -1
+
+        curr = self.head
+
+        while index != 0:
+            curr = curr.next
+            index -= 1
+
+        return curr.data
+
+    def addAtHead(self, key):
+        new_node = Node(key)
+        if not self.head:
+            self.head = new_node
+            self.tail = new_node
+        else:
+            new_node.next = self.head
+            self.head = new_node
+        self.size += 1
+
+    def addAtTail(self, key):
+        new_node = Node(key)
+        if not self.head:
+            self.head = new_node
+            self.tail = new_node
+        else:
+            self.tail.next = new_node
+
+        self.size += 1
+
+    def addAtIndex(self, index, key):
+        if index < 0 or index > self.size:
+            return -1
+        new_node = Node(key)
+        if index == 0:
+            self.addAtHead(key)
+        elif index == self.size - 1:
+            self.addAtTail(key)
+        else:
+            curr = self.head
+            while index - 1 != 0:   # here we keep track on index - 1 so that we can add after that element
+                curr = curr.next
+                index -= 1
+            curr.next = new_node
+            new_node.next = curr.next
+            self.size += 1
+
+    def deleteAtIndex(self, index):
+        if index < 0 or index >= self.size:
+            return -1
+        curr = self.head
+        if index == 0:
+            self.head = curr.next
+        elif index == self.size - 1:
+            while index - 1 != 0:
+                curr = curr.next
+            curr.next = 0
+            self.tail = curr
+        else:
+            while index != 0:
+                prev = curr
+                curr = curr.next
+                index -= 1
+            prev.next = curr.next
+        self.size -= 1
+
+
+
+myLinkedList = LinkedList()
+myLinkedList.addAtIndex(0, 200)
+myLinkedList.addAtIndex(1, 300)
+myLinkedList.addAtIndex(2, 400)
+myLinkedList.deleteAtIndex(1)
+print(myLinkedList.get(1))