import { Comparator } from '../types';
import { BaseCollection } from './base-collection';
export interface Heap<T> {
    push(element: T): void;
    pop(): T | undefined;
    top(): T | undefined;
}
export declare class Heap<T> extends BaseCollection<T> implements Heap<T> {
    private items;
    private comparator;
    constructor(comparator?: Comparator<T>);
    /**
     * Checks if the heap is empty. Returns true if empty, false otherwise.
     */
    isEmpty(): boolean;
    /**
     * Returns the number of elements in the heap.
     */
    size(): number;
    /**
     * Removes all elements from the heap.
     */
    clear(): void;
    /**
     * Moves an element up the heap to its correct position.
     */
    private heapifyUp;
    /**
     * Moves an element down the heap to its correct position.
     */
    private heapifyDown;
    /**
     * Checks if two heaps are equal.
     */
    equals(other: Heap<T>): boolean;
}