/**
 * Compares two values of type T.
 *
 * @public
 */
export type Comparator<T> = (a: T, b: T) => number;
/**
 * Minimum heap.
 *
 * @public
 */
export declare class Heap<T> {
    private readonly cmp;
    private items;
    constructor(cmp: Comparator<T>, data: T[]);
    /**
     * Is the heap empty?
     *
     * @public
     */
    empty(): boolean;
    /**
     * Push an item and sift up.
     *
     * @public
     */
    push(item: T): void;
    /**
     * Pop the minimum item.
     *
     * @public
     */
    pop(): T | undefined;
    /**
     * Sift down.
     */
    private _down;
    /**
     * Sift up.
     */
    private _up;
    private swap;
}