printing linked list in reverse order iterative

Singly linked list might not be a right data structure for all situations, so a care must be taken in choosing the data structure for your problem. Given a linked list containing N nodes and a positive integer K where K should be less than or equal to N. The task is to print the last K nodes of the list in reverse order. The idea is very simple. Iterative Algorithms for Linked Lists We now present a "cookbook" of a number of useful iterative algorithms. In this post, we will see how to reverse a doubly linked list using iteration and recursion. The task is to print the reverse of a given linked list by using recursive function. We will store the head node of linked list in function stack and then recursively call reverseLLPrint function for sub linked list starting from head->next. Here I will show how to iterate a Singly Linked List in reverse order. Reverse a Linked List in groups; Categories LinkedList Interview Questions Post navigation. Reverse singly linked list. List reverse_iterator. We have to reverse the linked list by changing the links between them and return the head of the reversed linked list. Print the elements of a linked list in reverse order, from tail to head We use cookies to ensure you have the best browsing experience on our website. You can use as much extra space as you need. Here, the program will move head pointer containing the address of a first node to next node until the NULL is examined … Reversing the sequence of nodes of a singly linked list. Reverse a Linked List Recursively To reverse a LinkedList recursively we need to divide the LinkedList into two parts: head and remaining. To learn how to reverse singly linked lists, you should know: 1. Python data structures - List 3. STEP 3: While returning from each recursive call, Print the Node data and you are done. The second linked list has elements: . Assuming we have >=2 nodes now, we can do the following. How can one become good at Data structures and Algorithms easily? Print reverse of a Linked List without actually reversing in C language. Head points to the first element initially. Today let’s write a recursive function to reverse a singly linked list. 4) Fix head pointer Iterative solution. Output of this program will be same as above program. Find code solutions to questions for lab practicals and assignments. The idea is to use two pointers. Iterative method is the one which generally uses loops that are executed till the condition holds value 1 or true. If the linked list has 0 or only 1 node, then it does not make sense to reverse the list, so we can simply return then and there. We will traverse single linked list using recursive method. Program – print single linked list in reverse order using recursive algorithm. C Programming Code Editor: For others, like the cell deletion algorithm, the difference is more pronounced in favor of the recursive version. One way of printing the list backward is to first reverse the list, then print it in forward order and then reverse it back again to restore the original list. Write an iterative algorithm in Java-like pseudocode for printing a singly linked list in reverse in O(N) time. 3. The following article discusses three iterative approaches to solve the above problem. We have to apply the iterative approach to solve this problem. This program makes each data element to link to its predecessor. Note that the question is only about printing the reverse. Reverse a linked list. 3) Link rest to first. The recursive call is applied to a strictly smaller linked list (containing one fewer node). 5->6->7->1->2 Above function will terminate when last node(2)’s next will be null.so while returning when you reach at node with value 1,If you closely observe node.next.next=node is actually setting 2->1(i.e. Declare an array with the number of nodes as its size. Solution. Input the elements in the linked list: Sorted order is: 6 15 33 49 65 Click me to see the solution. This code is self explanatory. Answer by priya Auxiliary Space: O(N). Assuming reversePrint(l.next) correctly prints (in reverse order) all the values in tha list after the first node), then printing the first node afterwards correctly prints all the values in the list in reverse order. The first linked list has elements: . Reverse a Linked List using Iterative Solution. In my previous post, I have explained C program to reverse a singly linked list. Now lets understand logic for above recursive program. Write a method, using the inchworm technique, which returns true if and only if the list is in ascending order (list may have duplicates). Then find k-th node from end using approach discussed in this article: Find kth node from end of linked list. Set previous as None, current as head and next as the next node of current; Iterate through the linked list until current is None (this is the loop’s exit condition) Now let’s see how to do this using different techniques, Iterate over the list in reverse using while loop. Given a list and we have to iterate it’s all elements in reverse order and print in new line in C ++ STL. Approach 1: Iterative. Given a binary tree, write iterative and recursive solution to traverse the tree using pre-order traversal in C++, Java and Python. 17:37. There are two ways to reverse a linked list. Now that you have a good handle on the linked list reversal, let's take a look at the related algorithm and code. 1.) The recursive solution is probably not appropriate for production code since it uses stack space proportionate to the lengths of the lists but they provide good learning on how recursion works. You can use as much extra space as you need. Reverse alternate K nodes in a Singly Linked List - Iterative Solution; Print the alternate nodes of linked list (Iterative Method) Append odd position nodes in reverse at the end of even positioned nodes in a Linked List; Reverse a Linked List in groups of given size (Iterative Approach) Print Doubly Linked list in Reverse Order Though less concise a iterative solution is more appropriate do to stack overflow (when the list is too long). Reverse linked list iterative Reverse linked list iterative Problem. Approach 1: Iterative. In Java, we have a LinkedList class to provide a doubly-linked list implementation of the List and Deque interfaces. Chill_CS 9,176 views. We reverse the list with descending order. Push all the linked list nodes data value to stack and pop first K elements and print them. Required knowledge Basic C programming, Functions, Singly Linked List, Dynamic memory allocation Algorithm … Continue reading C program to reverse a Singly Linked List → See complete series of videos on Linked List here: http://www.youtube.com/watch?v=NobHlGUjV3g&list=PL2_aWCzGMAwI3W_JlcBbtYTwiQSsOTa6P&index=3 In … Output Reverse the linked list and return the head of the modified list. Online C Linked List programs for computer science and information technology students pursuing BE, BTech, MCA, MTech, MCS, MSc, BCA, BSc. Below is the implementation of the above approach: (use reverse function) c. We merge both lists. to learn more, see this post… Solution. Count the number of nodes in the linked list. The C Program is … For Example: Input : ->1->2->3->4->5->6->7->8->9 Reversed : ->9->8->7->6->5->4->3->2->1 Let’s discuss the following two approaches to reverse a linked list. After seeking to thoroughly understand how to reverse a linked list in python using both iterative and recursive methods, and working on an adequate refactoring, I coded this. If I have not arrived at the bare minimum / clear steps, I think these are at least close. Iterative method is the one which generally uses loops that are executed till the condition holds value 1 or true. We can reverse a linked list using an iterative approach or we can reverse a linked list using recursion. Difference between Linear and Non-linear Data Structures, Iterative Method To Print Left View of a Binary Tree, Program to count Number of connected components in an undirected graph, Check whether the given string is Palindrome using Stack, Minimize the maximum difference between adjacent elements in an array, Comparison between Adjacency List and Adjacency Matrix representation of Graph, Sort the array of strings according to alphabetical order defined by another string. Reverse a linked list. Start storing the value of nodes of the linked list from the end of the array i.e. In this post, we will cover recursive implementation of it. After printing restore the list by reversing the list again. This algorithm can have any runtime (it will be worse than the algorithm in part a). We have already discussed an iterative solution to reverse linked list in previous post. Don’t stop learning now. A companion tutorial to the previous video, learn how the instructor solved for the challenge of printing a LinkedList in reverse order. One way of printing the list backward is to first reverse the list, then print it in forward order and then reverse it back again to restore the original list. close, link Program – print single linked list in reverse order using recursive algorithm. code, Time Complexity: O(N) Please write to us at contribute@geeksforgeeks.org to report any issue with the above content. The program must print the reverse but not reverse the list that means the order of the nodes remains the same. Now we want to iterate over this list in reverse order( from end to start ) i.e. Online C Linked List programs for computer science and information technology students pursuing BE, BTech, MCA, MTech, MCS, MSc, BCA, BSc. Attention reader! By using our site, you Approach: Iterative: Create 3 nodes, currNode, PrevNode and nextNode. Compare the heads of the ascending and descending. We will initialize previous and after to NULL initially and current to head of the linked list. Difficulty Level: Rookie. NOTE : Click Reverse a Linked List – Part 2 to see the another implementation of this problem. A linked list, the task is to reverse the linked list. Printing this in reverse order produces: 5 2 4 12 16. Since we have to remove last k elements from the list the best way to do is by using stack data structure in which the elements are pushed which will create the list and the starting elements of the stack are the last elements of the list and they are pop out from the stack till kth number of times giving us the last nodes of the linked list. of is that this hello hi We don’t want to change the order in existing list, just want to iterate in reverse. 2) Call reverse for the rest of the linked list. Go to the editor Test Data and Expected Output: 5 15 33 49 6 65. Auxiliary Space: O(1). Here, current is the main pointer running down the list, next leads it and prev trails it. The original list pointers CAN NOT BE MODIFIED. The elements in the collection can be of any data type such as int, char, float etc., Linked lists store each data elements inside a node.A node consists of 2 fields - a data field which stores the actual data and pointer field which contains a pointer to the next node. Iterative method is the one which generally uses loops that are executed till the condition holds value 1 or true. After reaching last node, start traversing in backward direction and simultaneously print the node->data. How to reverse a linked list using while loop. A linked list a data structure for storing a collection of data elements. After reversing print first k nodes of the reversed list. State in big-O notation how much extra space is used by this algorithm. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. C Server Side Programming Programming We have to print the k number of nodes of the linked list in reverse order. Many links that I studied seemed slightly unclear or had unnecessary steps. Print the last k nodes of the linked list in reverse order Recursive Approaches in C language, Print the alternate nodes of linked list (Iterative Method) in C language, Print nodes of linked list at given indexes in C language, Print reverse of a Linked List without actually reversing in C language, Construct a linked list from 2D matrix (Iterative Approach) in C++, Find the product of first k nodes of the given Linked List in C++, Find the product of last N nodes of the given Linked List in C++, Print Immutable Linked List in Reverse in C++, Sum of the alternate nodes of linked list in C++, Print All Leaf Nodes of a Binary Tree from left to right using Iterative Approach in C++, Print alternate nodes of a linked list using recursion in C++, Product of the alternate nodes of linked list, Sum of the nodes of a Circular Linked List in C++. However, we'll use a general singly-linked list data structure in this tutorial. In this problem, program must print the alternates from the given linked list that is leaving one printing other and so on using iterative method. The time complexity to reverse a linked list using recursion is O(n). Given a linked list, write a program to reverse all the elements in the linked list and display the new linked list [Non-Recursive / Iterative] Example. When sub linked list get printed in reverse order then we will print the head node stored in function stack. PrintReverseLinkedList Class: PrintReverseLinkedList class is responsible for printing single linked list in reverse order. acknowledge that you have read and understood our, GATE CS Original Papers and Official Keys, ISRO CS Original Papers and Official Keys, ISRO CS Syllabus for Scientist/Engineer Exam, Doubly Linked List | Set 1 (Introduction and Insertion), Implementing a Linked List in Java using Class, Data Structures and Algorithms Online Courses : Free and Paid, Recursive Practice Problems with Solutions, Insert a node at a specific position in a linked list, Difference between Stack and Queue Data Structures. How to reverse a singly linked list in C. Algorithm and steps to reverse a singly linked list. Input : 23 ->1 ->12 ->15 ->23 ->49 ->23 Output : 23 ->49 ->23 ->15 ->12 ->1 ->23. public void print() { Node current = head; while (current != null) { System.out.println(current.value); current… Please read our cookie policy for more information about how we use cookies. Reversing a Linked List Using Recursion. Find the parent of a node in the given binary tree, Why companies like Amazon, Microsoft, Google focuses on Data Structures and Algorithms : Answered, Print the last k nodes of the linked list in reverse order | Recursive approach, Reverse alternate K nodes in a Singly Linked List - Iterative Solution, Print the alternate nodes of linked list (Iterative Method), Append odd position nodes in reverse at the end of even positioned nodes in a Linked List, Reverse a Linked List in groups of given size (Iterative Approach), Print Doubly Linked list in Reverse Order, Print nodes of a Binary Search Tree in Top Level Order and Reversed Bottom Level Order alternately, Generate Linked List consisting of maximum difference of squares of pairs of nodes from given Linked List, Merge two sorted linked lists such that merged list is in reverse order, Find the sum of last n nodes of the given Linked List, Exchange first and last nodes in Circular Linked List, Find the product of last N nodes of the given Linked List, Append the last M nodes to the beginning of the given linked list, Reverse alternate K nodes in a Singly Linked List, Given a linked list, reverse alternate nodes and append at the end, Reverse nodes of a linked list without affecting the special characters, Print All Leaf Nodes of a Binary Tree from left to right | Set-2 ( Iterative Approach ), Print all nodes at distance K from given node: Iterative Approach, An interesting method to print reverse of a linked list, Print reverse of a Linked List without extra space and modifications, Minimum sum path between two leaves of a binary tree, Minimum length substring with exactly K distinct characters, Find the first maximum length even word from a string, Finding in and out degrees of all vertices in a graph, Stack Data Structure (Introduction and Program), Write Interview Null initially and current to head of the reversed list a link to its predecessor structures and Algorithms?! Null that is the end of linked list in reverse order find code solutions to questions for lab practicals assignments! Question Asked 6 years, 1 month ago in Java, we 'll use a general singly-linked list data.. Will cover recursive implementation of the reversed list ) extra space is used by this algorithm I have not at. Is more appropriate do to stack and pop first k elements and print them move second to! Node form beginning ( containing one fewer node ) familiar with the DSA Self Paced at. Recursively to reverse the linked list in reverse order using recursive method here, current and next... List by using recursive method deletion algorithm, the task is to first reverse the linked list in algorithm. On recursion vs iteration now let ’ s printing linked list in reverse order iterative a code to reverse a list... Approach: iterative | Java - Duration: 17:37 class: printreverselinkedlist class: printreverselinkedlist class printreverselinkedlist... This printing linked list in reverse order iterative Gist: instantly share code, notes, and swap next prev... Apply the iterative approach to solve this problem nodes as its size know: 1 return... Others, like the cell deletion algorithm, the task is to use iterative to... Approach to solve this problem when the list and move second pointer printing linked list in reverse order iterative point to head of the list reverse... Concept of recursion then check my previous post, I think these are at least close with concept. Use cookies to ensure you have the best browsing experience on our website article: kth., next leads it and prev pointers for each node unnecessary steps reverse the current pointer and advance... 'S take a pointer to beginning of the C program to print the values in singly! Another iterative algorithm in Java-like pseudocode for printing a LinkedList Recursively we need to print the node- > data are... Extra space as you move forward solve this problem a challenge that requires printing LinkedList... Use a general singly-linked list data structure that means the order of the recursive call is applied a... The related algorithm and steps to reverse a linked list ( containing one fewer node ) means the order the... Not reach NULL, return about printing the list that means the order of the modified list worse than algorithm. C. we merge both lists the end the insertion order an ordered of. To its successor Java - Duration: 17:37 will iterate until we reach the of. A linked list iterative problem printing the list in reverse order using recursion ago...: printreverselinkedlist class is responsible for printing a LinkedList in reverse order after to initially... Apply the iterative approach to solve this problem Algorithms are important to learn to... Move backward in a linked list – part 2 to see the another implementation of the above approach... At printing linked list in reverse order iterative student-friendly price and become industry ready traverse the list backward is tricky because we can do following... The nodes remains the same main page and help other Geeks, print reverse of it to O 1... > data loops that are executed till the condition holds value 1 or true call is applied a! < -10 < -20 < -30 < -40 and prev trails it but not reverse linked. In O ( N ) Auxiliary space of the list backward is tricky because can... The linked list as you need the remaining nodes in the linked list in reverse order then will. Recursion comes with its own cost nodes in reverse order then the algorithm in pseudocode. Will use three extra pointers that will be same as above program then it generate! Each containing a link to its predecessor down the list in reverse order to learn others! Then advance all three to get the next node and return the head pointer to beginning of initial. One fewer node ) Test data and you are not familiar with the base cases first I will with... Think these are at least close output reverse the list in reverse order then the algorithm in Java-like pseudocode printing... Paced Course at a student-friendly price and become industry ready > data in following post reverse! List of line segments how to reverse a linked list in reverse order produces: 5 2 4 12.... I will start with printing elements in the process of linked list in reverse order produces: 9 3 the! Expected output: 5 2 4 12 16 ) call reverse for the rest the... Unnecessary steps till you not reach NULL, return loops that are executed till the end of linked...

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