Recursive insertion and traversal linked list
We have discussed different methods of linked list insertion. How to recursively create a linked list?
Recursively inserting at the end: To create a Linked list using recursion follow these steps. Below steps insert a new node recursively at the end of linked list.
C++
// Function to insert a new node at the// end of linked list using recursion.Node* insertEnd(Node* head, int data){ // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == NULL) return newNode(data); // If we have not reached end, keep traversing // recursively. else head->next = insertEnd(head->next, data); return head;} |
Java
// Function to insert a new node at the// end of linked list using recursion.static Node insertEnd(Node head, int data){ // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == null) return newNode(data); // If we have not reached end, keep traversing // recursively. else head.next = insertEnd(head.next, data); return head;}// This code is contributed by rutvik_56 |
Python3
# Function to insert a new node at the# end of linked list using recursion.def insertEnd(head, data): # If linked list is empty, create a # new node (Assuming newNode() allocates # a new node with given data) if (head == None): return newNode(data) # If we have not reached end, # keep traversing recursively. else: head.next = insertEnd(head.next, data) return head# This code is contributed by divyeshrabadiya07 |
C#
// Function to insert a new node at the // end of linked list using recursion. static Node insertEnd(Node head, int data) { // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == null) return newNode(data); // If we have not reached end, keep traversing // recursively. else head.next = insertEnd(head.next, data); return head; }// This code is contributed by divyesh072019 |
Javascript
<script>// Function to insert a new node at the// end of linked list using recursion.function insertEnd(head , data){ // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == null) { return newNode(data); } // If we have not reached end, keep traversing // recursively. else { head.next = insertEnd(head.next, data); } return head;}// This code is contributed by shubhamsingh10</script> |
Recursively traversing the list:
The idea is simple, we print current node and recur for remaining list.
Implementation:
C++
void traverse(Node* head){ if (head == NULL) return; // If head is not NULL, print current node // and recur for remaining list cout << head->data << " "; traverse(head->next);} |
Java
static void traverse(Node head){ if (head == null) return; // If head is not null, print current node // and recur for remaining list System.out.print( head.data + " "); traverse(head.next);}// This code is contributed by SUBHAMSINGH10 |
Python3
def traverse(head): if (head == None): return # If head is not None, print current node # and recur for remaining list print(head.data, end = " "); traverse(head.next) # This code is contributed by Pratham76 |
C#
static void traverse(Node head){ if (head == null) return; // If head is not null, print current node // and recur for remaining list Console.Write(head.data + " "); traverse(head.next);} |
Javascript
function traverse(head){ if(head == null) return; // If head is not NULL, print current node // and recur for remaining list console.log(head.data + " "); traverse(head.next);}// This code is contributed by Yash Agarwal(yashagarwal2852002) |
Complete Program: Below is complete program to demonstrate working of insert and traverse a linked list.
C++
// Recursive C++ program to recursively insert// a node and recursively print the list.#include <bits/stdc++.h>using namespace std;struct Node { int data; Node* next;};// Allocates a new node with given dataNode *newNode(int data){ Node *new_node = new Node; new_node->data = data; new_node->next = NULL; return new_node;}// Function to insert a new node at the// end of linked list using recursion.Node* insertEnd(Node* head, int data){ // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == NULL) return newNode(data); // If we have not reached end, keep traversing // recursively. else head->next = insertEnd(head->next, data); return head;}void traverse(Node* head){ if (head == NULL) return; // If head is not NULL, print current node // and recur for remaining list cout << head->data << " "; traverse(head->next);}// Driver codeint main(){ Node* head = NULL; head = insertEnd(head, 6); head = insertEnd(head, 8); head = insertEnd(head, 10); head = insertEnd(head, 12); head = insertEnd(head, 14); traverse(head);} |
Java
// Recursive Java program to recursively insert// a node and recursively print the list.class GFG{ static class Node{ int data; Node next;};// Allocates a new node with given datastatic Node newNode(int data){ Node new_node = new Node(); new_node.data = data; new_node.next = null; return new_node;}// Function to insert a new node at the// end of linked list using recursion.static Node insertEnd(Node head, int data){ // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == null) return newNode(data); // If we have not reached end, keep traversing // recursively. else head.next = insertEnd(head.next, data); return head;}static void traverse(Node head){ if (head == null) return; // If head is not null, print current node // and recur for remaining list System.out.print( head.data + " "); traverse(head.next);}// Driver codepublic static void main(String args[]){ Node head = null; head = insertEnd(head, 6); head = insertEnd(head, 8); head = insertEnd(head, 10); head = insertEnd(head, 12); head = insertEnd(head, 14); traverse(head);}}// This code is contributed by andrew1234 |
Python3
# Recursive Python3 program to# recursively insert a node and# recursively print the list.import mathclass Node: def __init__(self, data): self.data = data self.next = None# Allocates a new node with given datadef newNode(data): new_node = Node(data) new_node.data = data new_node.next = None return new_node# Function to insert a new node at the# end of linked list using recursion.def insertEnd(head, data): # If linked list is empty, create a # new node (Assuming newNode() allocates # a new node with given data) if (head == None): return newNode(data) # If we have not reached end, # keep traversing recursively. else: head.next = insertEnd(head.next, data) return headdef traverse(head): if (head == None): return # If head is not None, print current node # and recur for remaining list print(head.data, end = " "); traverse(head.next)# Driver codeif __name__=='__main__': head = None head = insertEnd(head, 6) head = insertEnd(head, 8) head = insertEnd(head, 10) head = insertEnd(head, 12) head = insertEnd(head, 14) traverse(head)# This code is contributed by sapna singh |
C#
// Recursive C# program to recursively insert// a node and recursively print the list.using System;class GFG{ public class Node{ public int data; public Node next;};// Allocates a new node with given datastatic Node newNode(int data){ Node new_node = new Node(); new_node.data = data; new_node.next = null; return new_node;}// Function to insert a new node at the// end of linked list using recursion.static Node insertEnd(Node head, int data){ // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == null) return newNode(data); // If we have not reached end, keep traversing // recursively. else head.next = insertEnd(head.next, data); return head;}static void traverse(Node head){ if (head == null) return; // If head is not null, print current node // and recur for remaining list Console.Write(head.data + " "); traverse(head.next);}// Driver codepublic static void Main(String []args){ Node head = null; head = insertEnd(head, 6); head = insertEnd(head, 8); head = insertEnd(head, 10); head = insertEnd(head, 12); head = insertEnd(head, 14); traverse(head);}}// This code is contributed by 29AjayKumar |
Javascript
<script> // Recursive Javascript program to recursively insert // a node and recursively print the list. class Node { constructor(data) { this.next = null; this.data = data; } } // Allocates a new node with given data function newNode(data) { let new_node = new Node(data); return new_node; } // Function to insert a new node at the // end of linked list using recursion. function insertEnd(head, data) { // If linked list is empty, create a // new node (Assuming newNode() allocates // a new node with given data) if (head == null) return newNode(data); // If we have not reached end, keep traversing // recursively. else head.next = insertEnd(head.next, data); return head; } function traverse(head) { if (head == null) return; // If head is not null, print current node // and recur for remaining list document.write(head.data + " "); traverse(head.next); } let head = null; head = insertEnd(head, 6); head = insertEnd(head, 8); head = insertEnd(head, 10); head = insertEnd(head, 12); head = insertEnd(head, 14); traverse(head);// This code is contributed by mukesh07.</script> |
Output
6 8 10 12 14
Time Complexity: O(N), to traverse the linked list of size N.
Auxiliary Space: O(N), for recursion call stack
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