Recursive approach for alternating split of Linked List
Last Updated :
23 Jan, 2023
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++
#include <bits/stdc++.h>
using namespace std;
struct Node {
int data;
struct Node* next;
};
void push(Node** head, int new_data)
{
Node* new_node = new Node;
new_node->data = new_data;
new_node->next = (*head);
(*head) = new_node;
}
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);
}
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;
}
}
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
class GFG
{
static class Node
{
int data;
Node next;
};
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 ;
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);
}
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;
}
}
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);
}
}
|
Python
class Node( object ):
def __init__( self , d):
self .data = d
self . next = None
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
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 )
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
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)
|
C#
using System;
class GFG
{
public class Node
{
public int data;
public Node next;
};
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 ;
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);
}
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;
}
}
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);
}
}
|
Javascript
<script>
class Node
{
constructor()
{
this .data = 0;
this .next = null
}
};
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 ;
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 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;
}
}
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)
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