export declare type ComparatorFn = (a: any, b: any) => number;
export declare class PriorityQueue<T> {
    private heap;
    private compare;
    /**
     * Initializes a PriorityQueue class with given comparator function
     * @param {Function} comparator comparator function to compare heap entries
     */
    constructor(comparator?: ComparatorFn);
    /**
     * Returns index of parent node
     * @param {number} index arbitrary index
     * @returns {number} index of parent node
     */
    private parent;
    /**
     * Returns index of the left child
     * @param {number} index arbitrary index
     * @returns {number} index of left child
     */
    private left;
    /**
     * Returns index of the rigth  child
     * @param {number} index arbitrary index
     * @returns {number} index of right child
     */
    private right;
    /**
     * Returns true if node has left child
     * @param {number} index arbitrary index
     * @returns {boolean} whether node has left child
     */
    private hasLeft;
    /**
     * Returns true if node has right child
     * @param {number} index arbitrary index
     * @returns {boolean} whether node has right child
     */
    private hasRight;
    /**
     * Swaps two elements at given indices
     * @param {number} i first index
     * @param {number} j second index
     * @returns {void}
     */
    private swap;
    /**
     * Moves property at index to higher to restore heap property
     * @param {number} index arbitrary index
     * @returns {void}
     */
    private upheap;
    /**
     * Moves property at index to lower to restore heap property
     * @param {number} index arbitrary index
     * @returns {void}
     */
    private downheap;
    /**
     * Returns the heap size
     * @returns {number} size of the heap
     */
    size(): number;
    /**
     * Returns true if heap size is zero, false otherwise
     * @returns {boolean} true if heap is empty
     */
    isEmpty(): boolean;
    /**
     * Returns top element from the heap
     * @returns {T} the top element
     */
    peek(): T;
    /**
     * Inserts new value to the heap
     * @param {T} element value to insert
     * @returns {T} newly inserted value
     */
    enqueue(element: T): T;
    /**
     * Removes top element from top of heap and returns it
     * @returns {T} top element from the heap
     */
    dequeue(): T;
}