Create linked_list.py

Author: visz11

linked_list.py

@@ -0,0 +1,179 @@
+# Create a Node class to create a node
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+
+# Create a LinkedList class
+class LinkedList:
+    def __init__(self):
+        self.head = None
+
+    # Method to add a node at the beginning of the LL
+    def insertAtBegin(self, data):
+        new_node = Node(data)
+        new_node.next = self.head
+        self.head = new_node
+
+    # Method to add a node at any index
+    # Indexing starts from 0.
+    def insertAtIndex(self, data, index):
+        if index == 0:
+            self.insertAtBegin(data)
+            return
+
+        position = 0
+        current_node = self.head
+        while current_node is not None and position + 1 != index:
+            position += 1
+            current_node = current_node.next
+
+        if current_node is not None:
+            new_node = Node(data)
+            new_node.next = current_node.next
+            current_node.next = new_node
+        else:
+            print("Index not present")
+
+    # Method to add a node at the end of LL
+    def insertAtEnd(self, data):
+        new_node = Node(data)
+        if self.head is None:
+            self.head = new_node
+            return
+
+        current_node = self.head
+        while current_node.next:
+            current_node = current_node.next
+
+        current_node.next = new_node
+
+    # Update node at a given position
+    def updateNode(self, val, index):
+        current_node = self.head
+        position = 0
+        while current_node is not None and position != index:
+            position += 1
+            current_node = current_node.next
+
+        if current_node is not None:
+            current_node.data = val
+        else:
+            print("Index not present")
+
+    # Method to remove first node of linked list
+    def remove_first_node(self):
+        if self.head is None:
+            return
+
+        self.head = self.head.next
+
+    # Method to remove last node of linked list
+    def remove_last_node(self):
+        if self.head is None:
+            return
+
+        # If there's only one node
+        if self.head.next is None:
+            self.head = None
+            return
+
+        # Traverse to the second last node
+        current_node = self.head
+        while current_node.next and current_node.next.next:
+            current_node = current_node.next
+
+        current_node.next = None
+
+    # Method to remove a node at a given index
+    def remove_at_index(self, index):
+        if self.head is None:
+            return
+
+        if index == 0:
+            self.remove_first_node()
+            return
+
+        current_node = self.head
+        position = 0
+        while current_node is not None and current_node.next is not None and position + 1 != index:
+            position += 1
+            current_node = current_node.next
+
+        if current_node is not None and current_node.next is not None:
+            current_node.next = current_node.next.next
+        else:
+            print("Index not present")
+
+    # Method to remove a node from the linked list by its data
+    def remove_node(self, data):
+        current_node = self.head
+
+        # If the node to be removed is the head node
+        if current_node is not None and current_node.data == data:
+            self.remove_first_node()
+            return
+
+        # Traverse and find the node with the matching data
+        while current_node is not None and current_node.next is not None:
+            if current_node.next.data == data:
+                current_node.next = current_node.next.next
+                return
+            current_node = current_node.next
+
+        # If the data was not found
+        print("Node with the given data not found")
+
+    # Print the size of the linked list
+    def sizeOfLL(self):
+        size = 0
+        current_node = self.head
+        while current_node:
+            size += 1
+            current_node = current_node.next
+        return size
+
+    # Print the linked list
+    def printLL(self):
+        current_node = self.head
+        while current_node:
+            print(current_node.data)
+            current_node = current_node.next
+
+
+# create a new linked list
+llist = LinkedList()
+
+# add nodes to the linked list
+llist.insertAtEnd('a')
+llist.insertAtEnd('b')
+llist.insertAtBegin('c')
+llist.insertAtEnd('d')
+llist.insertAtIndex('g', 2)
+
+# print the linked list
+print("Node Data:")
+llist.printLL()
+
+# remove nodes from the linked list
+print("\nRemove First Node:")
+llist.remove_first_node()
+llist.printLL()
+
+print("\nRemove Last Node:")
+llist.remove_last_node()
+llist.printLL()
+
+print("\nRemove Node at Index 1:")
+llist.remove_at_index(1)
+llist.printLL()
+
+# print the linked list after all removals
+print("\nLinked list after removing a node:")
+llist.printLL()
+
+print("\nUpdate node Value at Index 0:")
+llist.updateNode('z', 0)
+llist.printLL()
+
+print("\nSize of linked list:", llist.sizeOfLL())