Javascript Program For Making Middle Node Head In A Linked List Last Updated : 02 Sep, 2024 Summarize Suggest changes Share Like Article Like Report Given a singly linked list, find middle of the linked list and set middle node of the linked list at beginning of the linked list. Examples:Input: 1 2 3 4 5 Output: 3 1 2 4 5Input: 1 2 3 4 5 6Output: 4 1 2 3 5 6 The idea is to first find middle of a linked list using two pointers, first one moves one at a time and second one moves two at a time. When second pointer reaches end, first reaches middle. We also keep track of previous of first pointer so that we can remove middle node from its current position and can make it head. JavaScript // Javascript program to make middle node // as head of Linked list // Link list node class Node { constructor(val) { this.data = val; this.next = null; } } let head; // Function to get the middle and set at // beginning of the linked list function setMiddleHead() { if (head == null) return; // To traverse list nodes one // by one one_node = head; // To traverse list nodes by // skipping one. two_node = head; // To keep track of previous of middle prev = null; while (two_node != null && two_node.next != null) { // for previous node of middle node prev = one_node; // Move one node each time two_node = two_node.next.next; // Move two node each time one_node = one_node.next; } // Set middle node at head prev.next = prev.next.next; one_node.next = head; head = one_node; } // To insert a node at the beginning of // linked list. function push(new_data) { // Allocate node new_node = new Node(new_data); // Link the old list of the new node new_node.next = head; // Move the head to point to the // new node head = new_node; } // A function to print a given linked list function printList(ptr) { while (ptr != null) { console.log(ptr.data); ptr = ptr.next; } } // Driver function // Create a list of 5 nodes head = null; let i; for (i = 5; i > 0; i--) push(i); console.log(" list before: "); printList(head); setMiddleHead(); console.log(" list After: "); printList(head); // This code is contributed by aashish1995 Output list before: 1 2 3 4 5 list After: 3 1 2 4 5 Complexity Analysis: Time Complexity: O(n) when n is the total no of nodes in a linked listSpace Complexity: O(1) because using constant spacePlease refer complete article on Make middle node head in a linked list for more details! Advertise with us K kartik Follow Similar Reads JavaScript Linked List Programs JavaScript Linked List Programs contain a list of articles based on programming. Linked List is a linear data structure that stores data in linearly connected nodes. Linked lists store elements sequentially, but doesn’t store the elements contiguously like an array. S. NoArticles1JavaScript Program 5 min read Implementation of LinkedList in Javascript In this article, we will be implementing the LinkedList data structure in Javascript.A linked list is a linear data structure where elements are stored in nodes, each containing a value and a reference (or pointer) to the next node. It allows for efficient insertion and deletion operations.Each node 5 min read Javascript Program For Searching An Element In A Linked List Write a function that searches a given key 'x' in a given singly linked list. The function should return true if x is present in linked list and false otherwise.bool search(Node *head, int x) For example, if the key to be searched is 15 and linked list is 14->21->11->30->10, then functio 3 min read Javascript Program For Inserting A Node In A Linked List We have introduced Linked Lists in the previous post. We also created a simple linked list with 3 nodes and discussed linked list traversal.All programs discussed in this post consider the following representations of the linked list. JavaScript// Linked List Class // Head of list let head; // Node 7 min read Javascript Program For Inserting Node In The Middle Of The Linked List Given a linked list containing n nodes. The problem is to insert a new node with data x at the middle of the list. If n is even, then insert the new node after the (n/2)th node, else insert the new node after the (n+1)/2th node.Examples: Input : list: 1->2->4->5 x = 3Output : 1->2->3- 4 min read Javascript Program For Writing A Function To Delete A Linked List A linked list is a linear data structure, in which the elements are not stored at contiguous memory locations. The elements in a linked list are linked using pointers. This article focuses on writing a function to delete a linked list.Implementation: JavaScript// Javascript program to delete // a li 1 min read Javascript Program For Deleting A Linked List Node At A Given Position Given a singly linked list and a position, delete a linked list node at the given position.Example: Input: position = 1, Linked List = 8->2->3->1->7Output: Linked List = 8->3->1->7Input: position = 0, Linked List = 8->2->3->1->7Output: Linked List = 2->3->1- 3 min read Javascript Program For Finding Length Of A Linked List Write a function to count the number of nodes in a given singly linked list.For example, the function should return 5 for linked list 1->3->1->2->1.Iterative Solution: 1) Initialize count as 0 2) Initialize a node pointer, current = head.3) Do following while current is not NULL a) curre 3 min read Javascript Program For Rotating A Linked List Given a singly linked list, rotate the linked list counter-clockwise by k nodes. Where k is a given positive integer. For example, if the given linked list is 10->20->30->40->50->60 and k is 4, the list should be modified to 50->60->10->20->30->40. Assume that k is smal 5 min read Javascript Program For Making Middle Node Head In A Linked List Given a singly linked list, find middle of the linked list and set middle node of the linked list at beginning of the linked list. Examples:Input: 1 2 3 4 5 Output: 3 1 2 4 5Input: 1 2 3 4 5 6Output: 4 1 2 3 5 6 The idea is to first find middle of a linked list using two pointers, first one moves on 3 min read Article Tags : JavaScript Tortoise-Hare-Approach JavaScript-Questions Like