Delete a linked list using recursion
Last Updated : 30 Aug, 2024
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Given a linked list, the task is to delete the linked list using recursion.
Examples:
Input: Linked List = 1 -> 2 -> 3 -> 4 -> 5 -> NULL
Output: NULL
Explanation: Linked List is DeletedInput: Linked List = 1 -> 12 -> 1 -> 4 -> 1 -> NULL
Output: NULL
Explanation: Linked List is Deleted
Approach :
The idea is to use recursion to traverse the linked list until we reach to end. While backtracking we keep on removing the current node in the linked list.
Below is the implementation of the above approach:
// C++ program to delete a linked list
// using recursion
#include <iostream>
using namespace std;
class Node {
public:
int data;
Node* next;
Node(int new_data) {
data = new_data;
next = nullptr;
}
};
// Given the head of a list, delete the list
// using recursion
void deleteList(Node* curr) {
// Base case: If the list is empty, return
if (curr == nullptr) {
return;
}
// Recursively delete the next node
deleteList(curr->next);
// Delete the current node
delete curr;
}
int main() {
// Create a hard-coded linked list:
// 1 -> 2 -> 3 -> 4 -> 5
Node* head = new Node(1);
head->next = new Node(2);
head->next->next = new Node(3);
head->next->next->next = new Node(4);
head->next->next->next->next = new Node(5);
deleteList(head);
head = nullptr;
cout << "Linked List deleted.";
return 0;
}
// C program to delete a linked list
// using recursion
#include <stdio.h>
#include <stdlib.h>
struct Node {
int data;
struct Node* next;
};
// Given the head of a list, delete the list
// using recursion
void deleteList(struct Node* curr) {
// Base case: If the list is empty, return
if (curr == NULL) {
return;
}
// Recursively delete the next node
deleteList(curr->next);
// Delete the current node
free(curr);
}
struct Node* createNode(int new_data) {
struct Node* new_node =
(struct Node*)malloc(sizeof(struct Node));
new_node->data = new_data;
new_node->next = NULL;
return new_node;
}
int main() {
// Create a hard-coded linked list:
// 1 -> 2 -> 3 -> 4 -> 5
struct Node* head = createNode(1);
head->next = createNode(2);
head->next->next = createNode(3);
head->next->next->next = createNode(4);
head->next->next->next->next = createNode(5);
deleteList(head);
head = NULL;
printf("Linked List deleted.");
return 0;
}
// Java program to delete a linked list
// using recursion
class Node {
int data;
Node next;
Node(int new_data) {
data = new_data;
next = null;
}
}
// Given the head of a list, delete the list
// using recursion
public class GfG {
static void deleteList(Node curr) {
// Base case: If the list is empty, return
if (curr == null) {
return;
}
// Recursively delete the next node
deleteList(curr.next);
// Delete the current node
curr = null;
}
public static void main(String[] args) {
// Create a hard-coded linked list:
// 1 -> 2 -> 3 -> 4 -> 5
Node head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(4);
head.next.next.next.next = new Node(5);
deleteList(head);
head = null;
System.out.print("Linked List deleted.");
}
}
# Python program to delete a linked list
# using recursion
class Node:
def __init__(self, new_data):
self.data = new_data
self.next = None
# Given the head of a list, delete the list
# using recursion
def delete_list(curr):
# Base case: If the list is empty, return
if curr is None:
return
# Recursively delete the next node
delete_list(curr.next)
# Delete the current node
curr = None
if __name__ == "__main__":
# Create a hard-coded linked list:
# 1 -> 2 -> 3 -> 4 -> 5
head = Node(1)
head.next = Node(2)
head.next.next = Node(3)
head.next.next.next = Node(4)
head.next.next.next.next = Node(5)
delete_list(head)
head = None
print("Linked List deleted.")
// C# program to delete a linked list
// using recursion
using System;
class Node {
public int Data;
public Node next;
public Node(int newData) {
Data = newData;
next = null;
}
}
// Given the head of a list, delete the list
// using recursion
class GfG {
static void DeleteList(Node curr) {
// Base case: If the list is empty, return
if (curr == null) {
return;
}
// Recursively delete the next node
DeleteList(curr.next);
// Delete the current node
curr = null;
}
static void Main() {
// Create a hard-coded linked list:
// 1 -> 2 -> 3 -> 4 -> 5
Node head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(4);
head.next.next.next.next = new Node(5);
DeleteList(head);
head = null;
Console.WriteLine("Linked List deleted.");
}
}
// JavaScript program to delete a
// linked list using recursion
class Node {
constructor(newData) {
this.data = newData;
this.next = null;
}
}
// Given the head of a list, delete the list
// using recursion
function deleteList(curr) {
// Base case: If the list is empty, return
if (curr === null) {
return;
}
// Recursively delete the next node
deleteList(curr.next);
// Delete the current node
curr = null;
}
// Create a hard-coded linked list:
// 1 -> 2 -> 3 -> 4 -> 5
let head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(4);
head.next.next.next.next = new Node(5);
deleteList(head);
head = null;
console.log("Linked List deleted.");
Output
Linked List deleted.
Time Complexity: O(n), where n is the number of nodes in the given linked list.
Auxiliary Space: O(n)
