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# Java Program For Insertion Sort In A Singly Linked List

We have discussed Insertion Sort for arrays. In this article we are going to discuss Insertion Sort for linked list.
Below is a simple insertion sort algorithm for a linked list.

```1) Create an empty sorted (or result) list.
2) Traverse the given list, do following for every node.
......a) Insert current node in sorted way in sorted or result list.

The main step is (2.a) which has been covered in the post Sorted Insert for Singly Linked List Below is implementation of above algorithm:

## Java

 `// Java program to sort link list``// using insertion sort``public` `class` `LinkedlistIS``{``    ``node head;``    ``node sorted;` `    ``class` `node``    ``{``        ``int` `val;``        ``node next;` `        ``public` `node(``int` `val)``        ``{``            ``this``.val = val;``        ``}``    ``}` `    ``void` `push(``int` `val)``    ``{``        ``// Allocate node``        ``node newnode = ``new` `node(val);` `        ``// Link the old list of the``        ``// new node``        ``newnode.next = head;` `        ``// Move the head to point to``        ``// the new node``        ``head = newnode;``    ``}` `    ``// Function to sort a singly linked list``    ``// using insertion sort``    ``void` `insertionSort(node headref)``    ``{``        ``// Initialize sorted linked list``        ``sorted = ``null``;``        ``node current = headref;` `        ``// Traverse the given linked list``        ``// and insert every node to sorted``        ``while` `(current != ``null``)``        ``{``            ``// Store next for next iteration``            ``node next = current.next;` `            ``// Insert current in sorted linked list``            ``sortedInsert(current);` `            ``// Update current``            ``current = next;``        ``}` `        ``// Update head_ref to point to``        ``// sorted linked list``        ``head = sorted;``    ``}` `    ``/* Function to insert a new_node in a list.``       ``Note that this function expects a pointer``       ``to head_ref as this can modify the head``       ``of the input linked list (similar to push()) */``    ``void` `sortedInsert(node newnode)``    ``{``        ``// Special case for the head end``        ``if` `(sorted == ``null` `||``            ``sorted.val >= newnode.val)``        ``{``            ``newnode.next = sorted;``            ``sorted = newnode;``        ``}``        ``else``        ``{``            ``node current = sorted;` `            ``/* Locate the node before the``               ``point of insertion */``            ``while` `(current.next != ``null` `&&``                   ``current.next.val < newnode.val)``            ``{``                ``current = current.next;``            ``}``            ``newnode.next = current.next;``            ``current.next = newnode;``        ``}``    ``}` `    ``// Function to print linked list``    ``void` `printlist(node head)``    ``{``        ``while` `(head != ``null``)``        ``{``            ``System.out.print(head.val + ``" "``);``            ``head = head.next;``        ``}``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``LinkedlistIS list = ``new` `LinkedlistIS();``        ``list.push(``5``);``        ``list.push(``20``);``        ``list.push(``4``);``        ``list.push(``3``);``        ``list.push(``30``);``        ``System.out.println(``        ``"Linked List before Sorting.."``);``        ``list.printlist(list.head);``        ``list.insertionSort(list.head);``        ``System.out.println(``        ``"LinkedList After sorting"``);``        ``list.printlist(list.head);``    ``}``}``// This code is contributed by Rishabh Mahrsee`

## Javascript

 `class Node {``  ``constructor(val) {``    ``this``.val = val;``    ``this``.next = ``null``;``  ``}``}` `class LinkedListIS {``  ``constructor() {``    ``this``.head = ``null``;``    ``this``.sorted = ``null``;``  ``}` `  ``push(val) {``    ``const newNode = ``new` `Node(val);``    ``newNode.next = ``this``.head;``    ``this``.head = newNode;``  ``}` `  ``insertionSort(headRef) {``    ``this``.sorted = ``null``;``    ``let current = headRef;` `    ``while` `(current !== ``null``) {``      ``const next = current.next;``      ``this``.sortedInsert(current);``      ``current = next;``    ``}` `    ``this``.head = ``this``.sorted;``  ``}` `  ``sortedInsert(newNode) {``    ``if` `(``this``.sorted === ``null` `|| ``this``.sorted.val >= newNode.val) {``      ``newNode.next = ``this``.sorted;``      ``this``.sorted = newNode;``    ``} ``else` `{``      ``let current = ``this``.sorted;` `      ``while` `(current.next !== ``null` `&& current.next.val < newNode.val) {``        ``current = current.next;``      ``}` `      ``newNode.next = current.next;``      ``current.next = newNode;``    ``}``  ``}` `  ``printList(head) {``    ``while` `(head !== ``null``) {``      ``console.log(head.val + ``" "``);``      ``head = head.next;``    ``}``  ``}``}` `const list = ``new` `LinkedListIS();``list.push(5);``list.push(20);``list.push(4);``list.push(3);``list.push(30);``console.log(``"Linked List before Sorting.."``);``list.printList(list.head);``list.insertionSort(list.head);``console.log(``"LinkedList After sorting"``);``list.printList(list.head);`

Output:

```Linked List before sorting
30  3  4  20  5