/**
 *
 * @package  vrkd/src/random
 * @author  Fernando Salazar
 */
/**
 * Select random integers within a range
 * and Keep track of used values.
 */
export default class UniqueInRange {
    /**
     * Starting range value
     */
    private _min;
    /**
     * End range value
     */
    private _max;
    /**
     * Number of options
     */
    private _range;
    /**
     * Store used numbers
     */
    private _used;
    /**
     * Declare minimum / maximum values
     */
    constructor($min?: number, $max?: number);
    /**
     * Get random number
     */
    render(): number;
    /**
     * Generates random number,
     * checks list of used keys
     * to return a non-used number.
     */
    private _random;
    /**
     * Returns an array of unused keys
     */
    private _unusedKeys;
}