Open In App

Recursive approach for alternating split of Linked List

Last Updated : 23 Jan, 2023
Comments
Improve
Suggest changes
Like Article
Like
Report

Given a linked list, split the linked list into two with alternate nodes.

Examples: 

Input : 1 2 3 4 5 6 7
Output : 1 3 5 7
         2 4 6

Input : 1 4 5 6
Output : 1 5
         4 6

We have discussed Iterative splitting of linked list.

The idea is to begin from two nodes first and second. Let us call these nodes as 'a' and 'b'. We recurs

Implementation:

C++ 
// CPP code to split linked list
#include <bits/stdc++.h>
using namespace std;

// Node structure
struct Node {
    int data;
    struct Node* next;
};

// Function to push nodes
// into linked list
void push(Node** head, int new_data)
{
    Node* new_node = new Node;
    new_node->data = new_data;
    new_node->next = (*head);
    (*head) = new_node;
}

// We basically remove link between 'a'
// and its next. Similarly we remove link
// between 'b' and its next. Then we recur
// for remaining lists.
void moveNode(Node* a, Node* b)
{
    if (b == NULL || a == NULL)
        return;

    if (a->next != NULL)
        a->next = a->next->next;

    if (b->next != NULL)
        b->next = b->next->next;

    moveNode(a->next, b->next);
}

// function to split linked list
void alternateSplitLinkedList(Node* head, Node** aRef,
                                        Node** bRef)
{
    Node* curr = head;
    *aRef = curr;
    *bRef = curr->next;
    moveNode(*aRef, *bRef);
}

void display(Node* head)
{
    Node* curr = head;
    while (curr != NULL) {
        printf("%d ", curr->data);
        curr = curr->next;
    }
}

// Driver code
int main()
{
    Node* head = NULL; 
    Node *a = NULL, *b = NULL;

    push(&head, 7);
    push(&head, 6);
    push(&head, 5);
    push(&head, 4);
    push(&head, 3);
    push(&head, 2);
    push(&head, 1);


    alternateSplitLinkedList(head, &a, &b);

    printf("a : ");
    display(a);
    printf("\nb : ");
    display(b);

    return 0;
}
Java 
// Java code to split linked list
class GFG
{
    
// Node structure
static class Node 
{
    int data;
    Node next;
};

// Function to push nodes
// into linked list
static Node push(Node head, int new_data)
{
    Node new_node = new Node();
    new_node.data = new_data;
    new_node.next = (head);
    (head) = new_node;
    return head;
}

static Node a = null, b = null;

// We basically remove link between 'a'
// and its next. Similarly we remove link
// between 'b' and its next. Then we recur
// for remaining lists.
static void moveNode(Node a, Node b)
{
    if (b == null || a == null)
        return;

    if (a.next != null)
        a.next = a.next.next;

    if (b.next != null)
        b.next = b.next.next;

    moveNode(a.next, b.next);
}

// function to split linked list
static void alternateSplitLinkedList(Node head)
{
    Node curr = head;
    a = curr;
    b = curr.next;
    Node aRef = a, bRef = b;
    moveNode(aRef, bRef);
}

static void display(Node head)
{
    Node curr = head;
    while (curr != null) 
    {
        System.out.printf("%d ", curr.data);
        curr = curr.next;
    }
}

// Driver code
public static void main(String args[])
{
    Node head = null; 
    head = push(head, 7);
    head = push(head, 6);
    head = push(head, 5);
    head = push(head, 4);
    head = push(head, 3);
    head = push(head, 2);
    head = push(head, 1);
    
    alternateSplitLinkedList(head);

    System.out.printf("a : ");
    display(a);
    System.out.printf("\nb : ");
    display(b);
}
}

// This code is contributed by Arnab Kundu
Python 
# Python code to split linked list 

# Node structure 
class Node(object): 
    def __init__(self, d): 
        self.data = d 
        self.next = None

# Function to push nodes 
# into linked list 
def push( head, new_data) :

    new_node = Node(0) 
    new_node.data = new_data 
    new_node.next = (head) 
    (head) = new_node 
    return head 

a = None
b = None

# We basically remove link between 'a' 
# and its next. Similarly we remove link 
# between 'b' and its next. Then we recur 
# for remaining lists. 
def moveNode( a, b) :
    if (b == None or a == None) :
        return
    if (a.next != None) :
        a.next = a.next.next
    if (b.next != None) :
        b.next = b.next.next

    moveNode(a.next, b.next) 

# function to split linked list 
def alternateSplitLinkedList(head) :
    
    curr = head
    global a
    global b
    a = curr 
    b = curr.next
    aRef = a
    bRef = b 
    moveNode(aRef, bRef) 
    return head;

def display(head) :

    curr = head 
    while (curr != None) :
    
        print( curr.data,end = " ") 
        curr = curr.next
    
# Driver code 
head = None
head = push(head, 7) 
head = push(head, 6) 
head = push(head, 5) 
head = push(head, 4) 
head = push(head, 3) 
head = push(head, 2) 
head = push(head, 1) 
    
head=alternateSplitLinkedList(head) 

print("a : ",end="") 
display(a) 
print("\nb : ",end="") 
display(b) 

# This code is contributed by Arnab Kundu
C# 
// C# code to split linked list
using System;

class GFG
{
    
// Node structure
public class Node 
{
    public int data;
    public Node next;
};

// Function to push nodes
// into linked list
static Node push(Node head, int new_data)
{
    Node new_node = new Node();
    new_node.data = new_data;
    new_node.next = (head);
    (head) = new_node;
    return head;
}

static Node a = null, b = null;

// We basically remove link between 'a'
// and its next. Similarly we remove link
// between 'b' and its next. Then we recur
// for remaining lists.
static void moveNode(Node a, Node b)
{
    if (b == null || a == null)
        return;

    if (a.next != null)
        a.next = a.next.next;

    if (b.next != null)
        b.next = b.next.next;

    moveNode(a.next, b.next);
}

// function to split linked list
static void alternateSplitLinkedList(Node head)
{
    Node curr = head;
    a = curr;
    b = curr.next;
    Node aRef = a, bRef = b;
    moveNode(aRef, bRef);
}

static void display(Node head)
{
    Node curr = head;
    while (curr != null) 
    {
        Console.Write("{0} ", curr.data);
        curr = curr.next;
    }
}

// Driver code
public static void Main(String []args)
{
    Node head = null; 
    head = push(head, 7);
    head = push(head, 6);
    head = push(head, 5);
    head = push(head, 4);
    head = push(head, 3);
    head = push(head, 2);
    head = push(head, 1);
    
    alternateSplitLinkedList(head);

    Console.Write("a : ");
    display(a);
    Console.Write("\nb : ");
    display(b);
}
}

// This code is contributed by PrinciRaj1992
JavaScript 
<script>

// JavaScript code to split linked list

// Node structure
class Node 
{
    constructor()
    {
        this.data = 0;
        this.next = null
    }
};

// Function to push nodes
// into linked list
function push(head, new_data)
{
    var new_node = new Node();
    new_node.data = new_data;
    new_node.next = (head);
    (head) = new_node;
    return head;
}

var a = null, b = null;

// We basically remove link between 'a'
// and its next. Similarly we remove link
// between 'b' and its next. Then we recur
// for remaining lists.
function moveNode(a, b)
{
    if (b == null || a == null)
        return;

    if (a.next != null)
        a.next = a.next.next;

    if (b.next != null)
        b.next = b.next.next;

    moveNode(a.next, b.next);
}

// function to split linked list
function alternateSplitLinkedList(head)
{
    var curr = head;
    a = curr;
    b = curr.next;
    var aRef = a, bRef = b;
    moveNode(aRef, bRef);
}

function display(head)
{
    var curr = head;
    while (curr != null) 
    {
        document.write(curr.data+ " ");
        curr = curr.next;
    }
}

// Driver code
var head = null; 
head = push(head, 7);
head = push(head, 6);
head = push(head, 5);
head = push(head, 4);
head = push(head, 3);
head = push(head, 2);
head = push(head, 1);

alternateSplitLinkedList(head);
document.write("a : ");
display(a);
document.write("<br>b : ");
display(b);

</script>

Output: 
a : 1 3 5 7 
b : 2 4 6

 

Time Complexity: O(N)
Auxiliary Space: O(N)


Next Article
Javascript Program For Alternating Split Of A Given Singly Linked List- Set 1

A
aditya1011
Improve
Article Tags :
Practice Tags :

Similar Reads

We use cookies to ensure you have the best browsing experience on our website. By using our site, you acknowledge that you have read and understood our Cookie Policy & Privacy Policy
Lightbox