/**
 * data-structure-typed
 *
 * @author Pablo Zeng
 * @copyright Copyright (c) 2022 Pablo Zeng <zrwusa@gmail.com>
 * @license MIT License
 */
import type { SkipLinkedListOptions } from '../../types';
export declare class SkipListNode<K, V> {
    key: K;
    value: V;
    forward: SkipListNode<K, V>[];
    constructor(key: K, value: V, level: number);
}
/**
 *
 */
export declare class SkipList<K, V> {
    /**
     * The constructor function initializes a SkipLinkedList object with optional options and elements.
     * @param elements - The `elements` parameter is an iterable containing key-value pairs `[K, V]`. It
     * is used to initialize the SkipLinkedList with the given key-value pairs. If no elements are
     * provided, the SkipLinkedList will be empty.
     * @param {SkipLinkedListOptions} [options] - The `options` parameter is an optional object that can
     * contain two properties:
     */
    constructor(elements?: Iterable<[K, V]>, options?: SkipLinkedListOptions);
    protected _head: SkipListNode<K, V>;
    /**
     * The function returns the head node of a SkipList.
     * @returns The method is returning a SkipListNode object with generic key type K and value type V.
     */
    get head(): SkipListNode<K, V>;
    protected _level: number;
    /**
     * The function returns the value of the protected variable _level.
     * @returns The level property of the object.
     */
    get level(): number;
    protected _maxLevel: number;
    /**
     * The function returns the maximum level.
     * @returns The value of the variable `_maxLevel` is being returned.
     */
    get maxLevel(): number;
    protected _probability: number;
    /**
     * The function returns the probability value.
     * @returns The probability value stored in the protected variable `_probability` is being returned.
     */
    get probability(): number;
    /**
     * Time Complexity: O(1)
     * Space Complexity: O(1)
     *
     * Get the value of the first element (the smallest element) in the Skip List.
     * @returns The value of the first element, or undefined if the Skip List is empty.
     */
    get first(): V | undefined;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * Get the value of the last element (the largest element) in the Skip List.
     * @returns The value of the last element, or undefined if the Skip List is empty.
     */
    get last(): V | undefined;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * The add function adds a new node with a given key and value to a Skip List data structure.
     * @param {K} key - The key parameter represents the key of the node that needs to be added to the skip list.
     * @param {V} value - The "value" parameter represents the value associated with the key that is being added to the Skip
     * List.
     */
    add(key: K, value: V): void;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * The function `get` retrieves the value associated with a given key from a skip list data structure.
     * @param {K} key - The `key` parameter is the key of the element that we want to retrieve from the data structure.
     * @returns The method `get(key: K)` returns the value associated with the given key if it exists in the data structure,
     * otherwise it returns `undefined`.
     */
    get(key: K): V | undefined;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * The function checks if a key exists in a data structure.
     * @param {K} key - The parameter "key" is of type K, which represents the type of the key being
     * checked.
     * @returns a boolean value.
     */
    has(key: K): boolean;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * The `delete` function removes a node with a specific key from a Skip List data structure.
     * @param {K} key - The key parameter represents the key of the node that needs to be removed from the skip list.
     * @returns The `delete` method returns a boolean value. It returns `true` if the key was successfully removed from the
     * skip list, and `false` if the key was not found in the skip list.
     */
    delete(key: K): boolean;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * Get the value of the first element in the Skip List that is greater than the given key.
     * @param key - the given key.
     * @returns The value of the first element greater than the given key, or undefined if there is no such element.
     */
    higher(key: K): V | undefined;
    /**
     * Time Complexity: O(log n)
     * Space Complexity: O(1)
     *
     * Get the value of the last element in the Skip List that is less than the given key.
     * @param key - the given key.
     * @returns The value of the last element less than the given key, or undefined if there is no such element.
     */
    lower(key: K): V | undefined;
    /**
     * Time Complexity: O(maxLevel)
     * Space Complexity: O(1)
     *
     * The function "_randomLevel" generates a random level based on a given probability and maximum level.
     * @returns the level, which is a number.
     */
    protected _randomLevel(): number;
}