Clockwise rotation of Linked List

<script>

// JavaScript implementation of the approach    

/* Link list node */
 class Node {
        constructor() {
            this.data = 0;
            this.next = null;
        }
    }

    /* A utility function to push a node */
    function push(head_ref , new_data) {
        /* allocate node */
      var new_node = new Node();

        /* put in the data */
        new_node.data = new_data;

        /* link the old list of the new node */
        new_node.next = (head_ref);

        /* move the head to point to the new node */
        (head_ref) = new_node;
        return head_ref;
    }

    /* A utility function to print linked list */
    function printList(node) {
        while (node != null) {
            document.write(node.data + " -> ");
            node = node.next;
        }
        document.write("null");
    }

    // Function that rotates the given linked list
    // clockwise by k and returns the updated
    // head pointer
    function rightRotate(head , k) {

        // If the linked list is empty
        if (head == null)
            return head;

        // len is used to store length 
        // of the linked list
        // tmp will point to the last
        // node after this loop
        var tmp = head;
        var len = 1;
        while (tmp.next != null) {
            tmp = tmp.next;
            len++;
        }

        // If k is greater than the size
        // of the linked list
        if (k > len)
            k = k % len;

        // Subtract from length to convert
        // it into left rotation
        k = len - k;

        // If no rotation needed then
        // return the head node
        if (k == 0 || k == len)
            return head;

        // current will either point to
        // kth or null after this loop
        var current = head;
        var cnt = 1;
        while (cnt < k && current != null) {
            current = current.next;
            cnt++;
        }

        // If current is null then k is equal to the
        // count of nodes in the list
        // Don't change the list in this case
        if (current == null)
            return head;

        // current points to the kth node
        var kthnode = current;

        // Change next of last node to previous head
        tmp.next = head;

        // Change head to (k+1)th node
        head = kthnode.next;

        // Change next of kth node to null
        kthnode.next = null;

        // Return the updated head pointer
        return head;
    }

    // Driver code
    

        /*
         * The constructed linked list is: 1.2.3.4.5
         */
        var head = null;
        head = push(head, 5);
        head = push(head, 4);
        head = push(head, 3);
        head = push(head, 2);
        head = push(head, 1);

        var k = 2;

        // Rotate the linked list
        var updated_head = rightRotate(head, k);

        // Print the rotated linked list
        printList(updated_head);

// This code contributed by Rajput-Ji

</script>

// JavaScript Program for the above approach
class Node{
    constructor(d){
        this.val = d;
        this.next = null;
    }
}

function build(head, val){
    if(head == null){
        head = new Node(val);
    }
    else{
        let temp = head;
        while(temp.next != null){
            temp = temp.next;
        }
        temp.next = new Node(val);
    }
    return head;
}

function rotate_clockwise(head, k){
    if(head == null) return null;
    
    let q = [];
    let temp = head;
    while(temp != null){
        q.push(temp);
        temp = temp.next;
    }
    
    k %= q.length;
    while(k--) //  popping from back and adding to it's front
    {
        q[q.length-1].next = q[0];
        q.unshift(q[q.length-1]);
        q.pop();
        q[q.length-1].next = null;
    }
    return q[0];
}

function print(head){
    while(head != null){
        console.log(head.val + " -> ");
        head = head.next;
    }
    console.log("NULL");
}

let head = null;
head = build(head, 1);
head = build(head, 2);
head = build(head, 3);
head = build(head, 4);
head = build(head, 5);
let k = 2;
let r = rotate_clockwise(head, k);
print(r);

// This code contributed by Yash Agarwal(yashagawal2852002)