export declare class DoublyLinkedListNode<T> {
    private element;
    private prev;
    private next;
    /**
     * Creates new DoublyLinkedListNode
     * @param {T} element
     * @param {DoublyLinkedListNode} prev
     * @param {DoublyLinkedListNode} next
     */
    constructor(element: T, prev: DoublyLinkedListNode<T>, next: DoublyLinkedListNode<T>);
    /**
     * Returns node value
     * @returns {T} node value
     */
    getElement(): T;
    /**
     * Returns next node
     * @returns {DoublyLinkedListNode} node
     */
    getNext(): DoublyLinkedListNode<T> | null;
    /**
     * Sets next node to given node
     * @param {DoublyLinkedListNode} next
     */
    setNext(next: DoublyLinkedListNode<T>): void;
    /**
     * Returns previous node
     * @returns {DoublyLinkedListNode} previous node
     */
    getPrev(): DoublyLinkedListNode<T> | null;
    /**
     * Sets previous node to given node
     * @param {DoublyLinkedListNode} prev
     */
    setPrev(prev: DoublyLinkedListNode<T>): void;
}
export declare class DoublyLinkedList<T> {
    private header;
    private trailer;
    private size;
    /**
     * Initializes header and trailer of the list
     */
    constructor();
    /**
     * Adds element to the head of the list
     * @param {T} element
     */
    addFirst(element: T): void;
    /**
     * Adds element to the tail of the list
     * @param {T} element
     */
    addLast(element: T): void;
    /**
     * Removes element from the head and returns it
     * @returns {T} removed node value
     */
    removeFirst(): T;
    /**
     * Removes element from the tail and returns it
     * @returns {T} removed node value
     */
    removeLast(): T;
    /**
     * Inserts new node between two nodes
     * @param {T} element
     * @param {DoublyLinkedListNode} predecessor
     * @param {DoublyLinkedListNode} successor
     */
    private addBetween;
    /**
     * Removes given node and returns its value
     * @param {DoublyLinkedListNode} node
     * @returns {T}
     */
    private remove;
    /**
     * Returns value of the head
     * @returns {T} value of first node
     */
    first(): T;
    /**
     * Returns value of the tail
     * @returns {T} value of last node
     */
    last(): T;
    /**
     * Returns size of the list
     * @returns {number} size of list
     */
    getSize(): number;
    /**
     * Returns true if the list is empty, fasle otherwise
     * @returns {boolean} true if the list is empty
     */
    isEmpty(): boolean;
}