1721. Swapping Nodes in a Linked List (javascript solution)

// We only need to switch the vals in the problem not the nodes.
// Create a dummy node at the front of the linked list.
// Move a pointer from the dummy up to the kth node and save the kth node to a variable called front.
// Create a new pointer at the dummy node call back.
// Continue moving the original pointer and the back pointer until the original pointer is null.
// Switch the values of back and front
var swapNodes = function(head, k) {
    let dummy = new ListNode(0, head);
    let front = dummy;
    let back = dummy;    
    let pointer = dummy;

    for(let i = k; i > 0; i--) {
        pointer = pointer.next
    }
    front = pointer
    while(pointer) {
        pointer = pointer.next
        back = back.next
    }

    const temp = front.val
    front.val = back.val
    back.val = temp

    return head;
};