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Move first element to end of a given Linked List
• Difficulty Level : Easy
• Last Updated : 26 Feb, 2020

Write a C function that moves first element to end in a given Singly Linked List. For example, if the given Linked List is 1->2->3->4->5, then the function should change the list to 2->3->4->5->1.

Algorithm:
Traverse the list till last node. Use two pointers: one to store the address of last node(last) and other for address of first node(first). After the end of loop do following operations.
ii) Set next of first as NULL (first->next = NULL).
iii) Set next of last as first ( last->next = first)

## C++

 `/* C++ Program to move first element to end ``   ``in a given linked list */``#include ``#include `` ` `/* A linked list node */``struct` `Node {``    ``int` `data;``    ``struct` `Node* next;``};`` ` `/* We are using a double pointer head_ref ``   ``here because we change head of the linked ``   ``list inside this function.*/``void` `moveToEnd(``struct` `Node** head_ref)``{``    ``/* If linked list is empty, or it contains ``       ``only one node, then nothing needs to be ``       ``done, simply return */``    ``if` `(*head_ref == NULL || (*head_ref)->next == NULL)``        ``return``;`` ` `    ``/* Initialize first and last pointers */``    ``struct` `Node* first = *head_ref;``    ``struct` `Node* last = *head_ref;`` ` `    ``/*After this loop last contains address ``    ``of last node in Linked List */``    ``while` `(last->next != NULL) {``        ``last = last->next;``    ``}`` ` `    ``/* Change the head pointer to point ``       ``to second node now */``    ``*head_ref = first->next;`` ` `    ``/* Set the next of first as NULL */``    ``first->next = NULL;`` ` `    ``/* Set the next of last as first */``    ``last->next = first;``}`` ` `/* UTILITY FUNCTIONS */``/* Function to add a node at the beginning ``   ``of Linked List */``void` `push(``struct` `Node** head_ref, ``int` `new_data)``{``    ``struct` `Node* new_node = ``new` `Node;``    ``new_node->data = new_data;``    ``new_node->next = (*head_ref);``    ``(*head_ref) = new_node;``}`` ` `/* Function to print nodes in a given linked list */``void` `printList(``struct` `Node* node)``{``    ``while` `(node != NULL) {``        ``printf``(``"%d "``, node->data);``        ``node = node->next;``    ``}``}`` ` `/* Driver program to test above function */``int` `main()``{``    ``struct` `Node* start = NULL;`` ` `    ``/* The constructed linked list is:``     ``1->2->3->4->5 */``    ``push(&start, 5);``    ``push(&start, 4);``    ``push(&start, 3);``    ``push(&start, 2);``    ``push(&start, 1);`` ` `    ``printf``(``"\n Linked list before moving first to end\n"``);``    ``printList(start);`` ` `    ``moveToEnd(&start);`` ` `    ``printf``(``"\n Linked list after moving first to end\n"``);``    ``printList(start);`` ` `    ``return` `0;``}`

## Java

 `/* Java Program to move first element to end ``in a given linked list */``class` `Sol``{``     ` `/* A linked list node */``static` `class` `Node``{ ``    ``int` `data; ``    ``Node next; ``}; `` ` `/* We are using a double pointer head_ref ``here because we change head of the linked ``list inside this function.*/``static` `Node moveToEnd( Node head_ref) ``{ ``    ``/* If linked list is empty, or it contains ``    ``only one node, then nothing needs to be ``    ``done, simply return */``    ``if` `(head_ref == ``null` `|| (head_ref).next == ``null``) ``        ``return` `null``; `` ` `    ``/* Initialize first and last pointers */``    ``Node first = head_ref; ``    ``Node last = head_ref; `` ` `    ``/*After this loop last contains address ``    ``of last node in Linked List */``    ``while` `(last.next != ``null``) ``    ``{ ``        ``last = last.next; ``    ``} `` ` `    ``/* Change the head pointer to point ``    ``to second node now */``    ``head_ref = first.next; `` ` `    ``/* Set the next of first as null */``    ``first.next = ``null``; `` ` `    ``/* Set the next of last as first */``    ``last.next = first; ``    ``return` `head_ref;``} `` ` `/* UTILITY FUNCTIONS */``/* Function to add a node at the beginning ``of Linked List */``static` `Node push( Node head_ref, ``int` `new_data) ``{ ``    ``Node new_node = ``new` `Node(); ``    ``new_node.data = new_data; ``    ``new_node.next = (head_ref); ``    ``(head_ref) = new_node;``    ``return` `head_ref;``} `` ` `/* Function to print nodes in a given linked list */``static` `void` `printList( Node node) ``{ ``    ``while` `(node != ``null``)``    ``{ ``        ``System.out.printf(``"%d "``, node.data); ``        ``node = node.next; ``    ``} ``} `` ` `/* Driver code */``public` `static` `void` `main(String args[])``{ ``    ``Node start = ``null``; `` ` `    ``/* The constructed linked list is: ``    ``1.2.3.4.5 */``    ``start = push(start, ``5``); ``    ``start = push(start, ``4``); ``    ``start = push(start, ``3``); ``    ``start = push(start, ``2``); ``    ``start = push(start, ``1``); `` ` `    ``System.out.printf(``"\n Linked list before moving first to end\n"``); ``    ``printList(start); `` ` `    ``start = moveToEnd(start); `` ` `    ``System.out.printf(``"\n Linked list after moving first to end\n"``); ``    ``printList(start); ``}``} `` ` `// This code is contributed by Arnab Kundu`

## C#

 `/* C# Program to move first element to end ``in a given linked list */``using` `System;`` ` `class` `GFG``{``     ` `/* A linked list node */``public` `class` `Node``{ ``    ``public` `int` `data; ``    ``public` `Node next; ``}; `` ` `/* We are using a double pointer head_ref ``here because we change head of the linked ``list inside this function.*/``static` `Node moveToEnd( Node head_ref) ``{ ``    ``/* If linked list is empty, or it contains ``    ``only one node, then nothing needs to be ``    ``done, simply return */``    ``if` `(head_ref == ``null` `|| (head_ref).next == ``null``) ``        ``return` `null``; `` ` `    ``/* Initialize first and last pointers */``    ``Node first = head_ref; ``    ``Node last = head_ref; `` ` `    ``/*After this loop last contains address ``    ``of last node in Linked List */``    ``while` `(last.next != ``null``) ``    ``{ ``        ``last = last.next; ``    ``} `` ` `    ``/* Change the head pointer to point ``    ``to second node now */``    ``head_ref = first.next; `` ` `    ``/* Set the next of first as null */``    ``first.next = ``null``; `` ` `    ``/* Set the next of last as first */``    ``last.next = first; ``    ``return` `head_ref;``} `` ` `/* UTILITY FUNCTIONS */``/* Function to add a node at the beginning ``of Linked List */``static` `Node push( Node head_ref, ``int` `new_data) ``{ ``    ``Node new_node = ``new` `Node(); ``    ``new_node.data = new_data; ``    ``new_node.next = (head_ref); ``    ``(head_ref) = new_node;``    ``return` `head_ref;``} `` ` `/* Function to print nodes in a given linked list */``static` `void` `printList( Node node) ``{ ``    ``while` `(node != ``null``)``    ``{ ``        ``Console.Write(``"{0} "``, node.data); ``        ``node = node.next; ``    ``} ``} `` ` `/* Driver code */``public` `static` `void` `Main(String []args)``{ ``    ``Node start = ``null``; `` ` `    ``/* The constructed linked list is: ``    ``1.2.3.4.5 */``    ``start = push(start, 5); ``    ``start = push(start, 4); ``    ``start = push(start, 3); ``    ``start = push(start, 2); ``    ``start = push(start, 1); `` ` `    ``Console.Write(``"\n Linked list before moving first to end\n"``); ``    ``printList(start); `` ` `    ``start = moveToEnd(start); `` ` `    ``Console.Write(``"\n Linked list after moving first to end\n"``); ``    ``printList(start); ``}``}`` ` `// This code is contributed by 29AjayKumar`

## Python3

 `# Python3 Program to move first element to end ``# in a given linked list `` ` `# A linked list node ``class` `Node:``    ``def` `__init__(``self``):``        ``self``.data ``=` `0``        ``self``.``next` `=` `None`` ` `# We are using a double pointer head_ref ``# here because we change head of the linked ``# list inside this function.``def` `moveToEnd( head_ref) :`` ` `    ``# If linked list is empty, or it contains ``    ``# only one node, then nothing needs to be ``    ``# done, simply return ``    ``if` `(head_ref ``=``=` `None` `or` `(head_ref).``next` `=``=` `None``) :``        ``return` `None`` ` `    ``# Initialize first and last pointers ``    ``first ``=` `head_ref ``    ``last ``=` `head_ref `` ` `    ``# After this loop last contains address ``    ``# of last node in Linked List ``    ``while` `(last.``next` `!``=` `None``) :``     ` `        ``last ``=` `last.``next``     ` `    ``# Change the head pointer to point ``    ``# to second node now ``    ``head_ref ``=` `first.``next`` ` `    ``# Set the next of first as None ``    ``first.``next` `=` `None`` ` `    ``# Set the next of last as first ``    ``last.``next` `=` `first ``    ``return` `head_ref`` ` `# UTILITY FUNCTIONS ``# Function to add a node at the beginning ``# of Linked List ``def` `push( head_ref, new_data) :`` ` `    ``new_node ``=` `Node() ``    ``new_node.data ``=` `new_data ``    ``new_node.``next` `=` `(head_ref) ``    ``(head_ref) ``=` `new_node``    ``return` `head_ref`` ` `# Function to print nodes in a given linked list ``def` `printList(node) :`` ` `    ``while` `(node !``=` `None``):``     ` `        ``print``(node.data, end ``=` `" "``) ``        ``node ``=` `node.``next``     ` `# Driver code `` ` `start ``=` `None`` ` `# The constructed linked list is: ``#1.2.3.4.5 ``start ``=` `push(start, ``5``) ``start ``=` `push(start, ``4``) ``start ``=` `push(start, ``3``) ``start ``=` `push(start, ``2``) ``start ``=` `push(start, ``1``) `` ` `print``(``"\n Linked list before moving first to end"``) ``printList(start) `` ` `start ``=` `moveToEnd(start) `` ` `print``(``"\n Linked list after moving first to end"``) ``printList(start) `` ` `# This code is contributed by Arnab Kundu`
Output:
```Linked list before moving first to end
1 2 3 4 5
Linked list after moving first to end
2 3 4 5 1
```

Time Complexity: O(n) where n is the number of nodes in the given Linked List.

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