import { RedBlackTreeStructure } from '../internals';
/**
 * Adds a new key and value to the tree, or updates the value if the key was previously absent from the tree. If the new
 * value is the equal to a value already associated with the specified key, no change is made, and the original tree is
 * returned.
 *
 * @export
 * @template K The type of keys in the tree
 * @template V The type of values in the tree
 * @param {K} key The key of the entry to be updated or inserted
 * @param {V} value The value that should be associated with the key
 * @param {RedBlackTreeStructure<K, V>} tree The tree to be updated
 * @returns {RedBlackTreeStructure<K, V>} An updated copy of the tree, or the same tree if the input tree was already mutable
 */
export declare function set<K, V = null>(key: K, value: V, tree: RedBlackTreeStructure<K, V>): RedBlackTreeStructure<K, V>;