Reverse a Linked List - Python Last Updated : 21 Feb, 2025 Summarize Suggest changes Share Like Article Like Report Given pointer to the head node of a linked list, the task is to reverse the linked list. We need to reverse the list by changing links between nodes.Examples: Input: head: 1 -> 2 -> 3 -> 4 -> NULLOutput: head: 4 -> 3 -> 2 -> 1 -> NULLExplanation: Reversed Linked List:Reversed Linked ListInput: head: 1 -> 2 -> 3 -> 4 -> 5 -> NULLOutput: head: 5 -> 4 -> 3 -> 2 -> 1 -> NULLExplanation: Reversed Linked List:Reversed Linked ListInput : NULLOutput : NULLInput : 1->NULLOutput : 1->NULL1. Iterative Method The idea is to reverse the links of all nodes using three pointers: prev: pointer to keep track of the previous nodecurr: pointer to keep track of the current node next: pointer to keep track of the next nodeStarting from the first node, initialize curr with the head of linked list and next with the next node of curr. Update the next pointer of curr with prev. Finally, move the three pointer by updating prev with curr and curr with next. Python class Node: # Constructor to initialize the node object def __init__(self, data): self.data = data self.next = None class LinkedList: # Function to initialize head def __init__(self): self.head = None # Function to reverse the linked list def reverse(self): prev = None current = self.head while(current is not None): next = current.next current.next = prev prev = current current = next self.head = prev # Function to insert a new node at the beginning def push(self, new_data): new_node = Node(new_data) new_node.next = self.head self.head = new_node # Utility function to print the LinkedList def printList(self): temp = self.head while(temp): print (temp.data,end=" ") temp = temp.next # Driver program to test above functions llist = LinkedList() llist.push(20) llist.push(4) llist.push(15) llist.push(85) print ("Given Linked List") llist.printList() llist.reverse() print ("\nReversed Linked List") llist.printList() OutputGiven Linked List 85 15 4 20 Reversed Linked List 20 4 15 85 Time Complexity: O(N)Auxiliary Space: O(1)2. A Simpler and Tail Recursive Method The idea is to reach the last node of the linked list using recursion then start reversing the linked list from the last node. Python class Node: # Constructor to initialize the node object def __init__(self, data): self.data = data self.next = None class LinkedList: # Function to initialize head def __init__(self): self.head = None def reverseUtil(self, curr, prev): # If last node mark it head if curr.next is None: self.head = curr # Update next to prev node curr.next = prev return # Save curr.next node for recursive call next = curr.next # And update next curr.next = prev self.reverseUtil(next, curr) # This function mainly calls reverseUtil() # with previous as None def reverse(self): if self.head is None: return self.reverseUtil(self.head, None) # Function to insert a new node at the beginning def push(self, new_data): new_node = Node(new_data) new_node.next = self.head self.head = new_node # Utility function to print the LinkedList def printList(self): temp = self.head while(temp): print(temp.data,end=" ") temp = temp.next # Driver program llist = LinkedList() llist.push(8) llist.push(7) llist.push(6) llist.push(5) llist.push(4) llist.push(3) llist.push(2) llist.push(1) print("Given linked list") llist.printList() llist.reverse() print("\nReverse linked list") llist.printList() OutputGiven linked list 1 2 3 4 5 6 7 8 Reverse linked list 8 7 6 5 4 3 2 1 Time Complexity: O(N)Auxiliary Space: O(1)Please refer Reverse a linked list for more details! Advertise with us Next Article Reverse a Linked List - Python K kartik Follow Similar Reads Python Programs Practice with Python program examples is always a good choice to scale up your logical understanding and programming skills and this article will provide you with the best sets of Python code examples.The below Python section contains a wide collection of Python programming examples. These Python co 11 min read Basic ProgramsHow to Add Two Numbers in PythonThe task of adding two numbers in Python involves taking two input values and computing their sum using various techniques . For example, if a = 5 and b = 7 then after addition, the result will be 12.Using the "+" Operator+ operator is the simplest and most direct way to add two numbers . It perform 4 min read Find Maximum of two numbers in PythonFinding the maximum of two numbers in Python helps determine the larger of the two values. 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