export declare class Node<Item> {
    item: Item;
    next: Node<Item>;
}
/**
 *  The Bag class represents a bag (or multiset) of
 *  generic items. It supports insertion and iterating over the
 *  items in arbitrary order.
 *  <p>
 *  This implementation uses a singly linked list with a static nested class Node.
 *  See {@link LinkedBag} for the version from the
 *  textbook that uses a non-static nested class.
 *  See {@link ResizingArrayBag} for a version that uses a resizing array.
 *  The <em>add</em>, <em>isEmpty</em>, and <em>size</em> operations
 *  take constant time. Iteration takes time proportional to the number of items.
 *  <p>
 *  For additional documentation, see <a href="https://algs4.cs.princeton.edu/13stacks">Section 1.3</a> of
 *  <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne.
 *
 *  @param <Item> the generic type of an item in this bag
 */
export default class Bag<Item> implements Iterable<Item> {
    private first;
    private n;
    private modCount;
    /**
     * Initializes an empty bag.
     */
    constructor();
    /**
     * Returns true if this bag is empty.
     *
     * @return `true` if this bag is empty;
     *         `false` otherwise
     */
    isEmpty(): boolean;
    /**
     * Returns the number of items in this bag.
     *
     * @return the number of items in this bag
     */
    size(): number;
    /**
     * Adds the item to this bag.
     *
     * @param  item the item to add to this bag
     */
    add(item: Item): void;
    /**
     * Returns an iterator that iterates over the items in this bag in arbitrary order.
     *
     * @return an iterator that iterates over the items in this bag in arbitrary order
     */
    [Symbol.iterator](): {
        next(): IteratorResult<Item, any>;
    };
    /**
     * Returns a string representation of this queue.
     *
     * @return the sequence of items in FIFO order, separated by spaces
     */
    toString(): string;
}