import { LinkedList } from "../../interfaces/linked-list";
import { ListNode } from "../../classes/list-node";
export declare class DoublyLinkedList implements LinkedList {
    private head;
    private tail;
    private _size;
    /**
     * The size of the list
     */
    get size(): number;
    /**
     * The head of the list
     */
    get first(): ListNode;
    /**
     * The tail of the list
     */
    get last(): ListNode;
    /**
     * Adds a node to the end of the list
     * @param val the value of the new node
     * @returns {number} the new size of the list
     */
    push(val: any): number;
    /**
     * Removes the tail (last) node of the list.
     * @returns {ListNode} the node that was removed
     */
    pop(): ListNode;
    /**
     * Removes the head (first) node of the list
     * @returns {ListNode} the node that was removed
     */
    shift(): ListNode;
    /**
     * returns the node at the specified index.
     * @param index the index of the node
     */
    getNodeAt(index: number): ListNode;
    /**
     * adds a new node to the beginning of the list
     * @param val the value of the new node
     * @returns {number} the new size of the list.
     */
    unshift(val: any): number;
    /**
     * adds a node to the specified index in the list.
     * @param val the value of the new node
     * @param index the position of the new node
     * @returns {number} the new size of the list
     */
    insert(val: any, index: number): number;
}