src/public/tree-multimap.js
/** An implementation of red-black tree */
const {Tree} = require('../internal/tree');
/** Classes that regulate whether tree nodes hold keys only, or key-value pairs */
const {KeyValuePolicy} = require('../internal/policies');
/** Node for a red-black tree */
const {TreeNode} = require('../internal/tree-node');
/**
* TreeMultiMap is an associative container that stores elements formed by
* a combination of a key value and a mapped value, following a specific order,
* and where multiple elements can have equivalent keys.
*
* In a TreeMultiMap, the key values are generally used to sort and uniquely
* identify the elements, while the mapped values store the content
* associated to this key. The types of key and mapped value may differ.
*
* ## Container properties
* * **Associative** - Elements in associative containers are referenced
* by their key and not by their absolute position in the container.
* * **Ordered** - The elements in the container follow a strict order
* at all times. All inserted elements are given a position in this order.
* * **Map** - Each element associates a key to a mapped value. Keys are meant
* to identify the elements whose main content is the mapped value.
* * **Multiple equivalent keys** - Multiple elements in the container
* can have equivalent keys.
*
* @example
* let map = new TreeMultiMap();
* // add few values
* map.set(1, 'a');
* map.set(2, 'b');
* map.set(2, 'c');
* // find a value by key
* let v = map.get(1); // << 'a'
* find all values for a given key
* // print all key-value pairs
* let from = map.lowerBound(2);
* let to = map.upperBound(2);
* let it = from;
* while (!it.equals(to)) {
* console.log(it.key);
* it.next();
* }
*/
class TreeMultiMap {
/*======================================================
* Methods of ES6 Map
*======================================================*/
/**
* Creates an empty, or a pre-initialized map.
* @param {*} [iterable] Another iterable object whose key-value pairs are added into the newly created map.
* @example
* // Create an empty map
* let map1 = new TreeMultiMap();
* // Create and initialize map
* let map2 = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
*/
constructor(iterable) {
/** Internal tree */
this.__t = new Tree();
this.__t.valuePolicy = new KeyValuePolicy();
if ((iterable !== undefined)
&& (iterable !== null)) {
if (iterable[Symbol.iterator] !== undefined) {
// copy contents
for (let [k, v] of iterable) {
this.set(k, v);
}
}
else {
throw new Error('TreeMultiMap constructor accepts only iterable objects');
}
}
}
/**
* String tag of this class
* @returns {String}
* @example
* Object.prototype.toString.call(new TreeMultiMap()); // "[object TreeMultiMap]"
*/
get [Symbol.toStringTag]() {
return 'TreeMultiMap';
}
/**
* Allows to create programmatically an instance of the same class
* @returns constructor object for this class.
* @example
* let map = new TreeMultiMap();
* let constrFunc = Object.getPrototypeOf(map).constructor[Symbol.species];
* let map2 = new constrFunc();
*/
static get [Symbol.species]() {
return TreeMultiMap;
}
/**
* Removes all key-value pairs.
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* map.clear();
* console.log(map.size); // 0
*/
clear() {
this.__t.clear();
}
/**
* Removes key-value pair with the specified key if such entry exists. Does nothing otherwise.
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* map.delete(2);
* console.log(map.toString()); // {1:A,3:C}
*/
delete(key) {
let it = this.__t.find(key);
if (!it.equals(this.__t.end())) {
this.__t.erase(it.node);
}
}
/**
* Forward ES6 iterator for all key-value pairs in ascending order of the keys.
* @returns {JsIterator}
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let [key,value] of map.entries()) {
* console.log(`key: ${key}, value: ${value}`);
* }
*/
entries() {
return this.__t.entries();
}
/**
* Iterates all key-value pairs using a callback in ascending order of the keys.
* Note that ES6 specifies the order of key value parameters in the callback differently from for-of loop.
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* map.forEach(function(value, key, container) {
* console.log(`key: ${key}, value: ${value}`);
* });
*/
forEach(callback) {
for (let [k, v] of this.__t) {
callback(v, k, this);
}
}
/**
* Finds value associated with the specified key. If specified key does not exist then undefined is returned.
* @returns {*}
* @param {*} key a value of any type that can be compared with a key
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* let v = map.get(3); // 'C'
* * let v = map.get(4); // returns undefined
*/
get(key) {
let it = this.__t.find(key);
if (!it.equals(this.__t.end())) {
return it.value;
}
else {
return undefined;
}
}
/**
* A boolean indicator whether map contains a key-value pair with the specified key
* @returns {Boolean}
* @param {*} key a value of any type that can be compared with a key
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* let b = map.get(3); // true
*/
has(key) {
let it = this.__t.find(key);
if (!it.equals(this.__t.end())) {
return true;
}
else {
return false;
}
}
/**
* Forward ES6 iterator for all keys in ascending order of the keys.
* @returns {JsIterator}
* @example
* // iterate all keys
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let k of map.keys()) {
* console.log(k); // 1, 2, 3
* }
* // iterate all keys in reverse order
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let k of map.keys().backward()) {
* console.log(k); // 3, 2, 1
* }
*/
keys() {
return this.__t.keys();
}
/**
* Adds a key-value pair to the map. Multiple key-value pairs with the same key are allowed in TreeMultiMap.
* @param {*} key
* @param {*} value
* @example
* let map = new TreeMultiMap();
* map.set(1, 'A');
* map.set(1, 'B');
* map.set(2, 'C');
* for (let k of map.values()) {
* console.log(k); // A, B, C
* }
*/
set(key, value) {
let n = new TreeNode();
n.key = key;
n.value = value;
this.__t.insertMulti(n);
}
/**
* Number of key-value pairs in the map.
* @returns {Number}
*/
get size() {
return this.__t.size();
}
/**
* Forward ES6 iterator for all values in ascending order of the keys.
* @returns {JsITerator}
* @example
* // iterate all values
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let v of map.values()) {
* console.log(v); // 'A', 'B', 'C'
* }
* // iterate all values in reverse order
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let v of map.values().backward()) {
* console.log(v); // 'C', 'B', 'A'
* }
*/
values() {
return this.__t.values();
}
/**
* Forward ES6 iterator for all key-value pairs in ascending order of the keys. The same as entries() method
* @returns {JsIterator}
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let [key,value] of map) {
* console.log(`key: ${key}, value: ${value}`);
* }
*/
[Symbol.iterator]() {
return this.__t[Symbol.iterator]();
}
/*======================================================
* More methods
*======================================================*/
/**
* ES6 reverse iterator for all key-value pairs in descending order of the keys.
* @returns {JsReverseIterator}
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* for (let [key,value] of map.backwards()) {
* console.log(`key: ${key}, value: ${value}`);
* }
*/
backward() {
return this.__t.backward();
}
/**
* Sets custom comparison function if key values are not of primitive types.
* Callback is a 3-way comparison function accepts two key values (lhs, rhs). It is expected to return
* +1 if the value of rhs is greater than lhs
* -1 if the value of rhs is less than lhs
* 0 if values are the same
*/
set compareFunc(func) {
this.clear();
this.__t.compare = func;
}
/*======================================================
* STL-like methods
*======================================================*/
/**
* Forward iterator to the first element
* @returns {Iterator}
* @example
* let m = new TreeMultiMap();
* ...
* for (let it = m.begin(); !it.equals(m.end()); it.next()) {
* console.log(`key: ${it.key}, value: ${it.value}`);
* }
*/
begin() {
return this.__t.begin();
}
/**
* Forward iterator to the element following the last element
* @returns {Iterator}
* @example
* let m = new TreeMultiMap();
* ...
* for (let it = m.begin(); !it.equals(m.end()); it.next()) {
* console.log(`key: ${it.key}, value: ${it.value}`);
* }
*/
end() {
return this.__t.end();
}
/**
* Finds an element with key equivalent to the specified one. If such key does not exist end() iterator is returned.
* @param {*} key
* @returns {Iterator}
* @example
* let m = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* ...
* let it = m.find(1);
* if (!it.equals(m.end())) {
* console.log(`key: ${it.key}, value: ${it.value}`); // 1, 'A'
* }
*/
find(key) {
return this.__t.find(key);
}
/**
* Adds key-value pair if such key does not exist in the map
* @param {*} key
* @param {*} value
* @returns {InsertionResult} - indicates whether a node was added and provides iterator to it.
* @example
* let m = new TreeMultiMap();
* let res = m.insertUnique(1, 'A');
* if (res.wasInserted) {
* console.log(`Inserted ${res.iterator.value}`); // prints A
* }
* res = m.insertUnique(1, 'B') // this step has no effect on the map
* if (res.wasInserted) {
* console.log(`Inserted ${res.iterator.key}`); // not executed
* }
*/
insertUnique(key, value) {
let n = new TreeNode();
n.key = key;
n.value = value;
return this.__t.insertUnique(n);
}
/**
* Adds key-value pair if such key does not exist in the map. Replaces value if such key exists
* @param {*} key
* @param {*} value
* @returns {InsertionResult} - indicates whether a node was added and provides iterator to it.
* @example
* let m = new TreeMultiMap();
* let res = m.insertOrReplace(1, 'A');
* if (res.wasInserted) {
* console.log(`Inserted ${res.iterator.value}`); // prints A
* }
* res = m.insertOrReplace(1, 'B') // replaces value on the existing node
* if (res.wasInserted) {
* console.log(`Inserted ${res.iterator.key}`); // prints B
* }
*/
insertOrReplace(key, value) {
let n = new TreeNode();
n.key = key;
n.value = value;
return this.__t.insertOrReplace(n);
}
/**
* Adds key-value pair. If such key already exists in the map then adds another node with the same key and a new value.
* @param {*} key
* @param {*} value
* @returns {InsertionResult} - indicates whether a node was added and provides iterator to it.
* @example
* let m = new TreeMultiMap();
* let res = m.insertMulti(1, 'A');
* if (res.wasInserted) {
* console.log(`Inserted ${res.iterator.value}`); // prints A
* }
* res = m.insertMulti(1, 'B') // adds a new node
* if (res.wasInserted) {
* console.log(`Inserted ${res.iterator.value}`); // prints B
* it.prev();
* console.log(`Previously inserted ${res.iterator.value}`); // prints A
* }
*/
insertMulti(key, value) {
let n = new TreeNode();
n.key = key;
n.value = value;
return this.__t.insertMulti(n);
}
/**
* Removes key-value pair for the specified iterator.
* @param {Iterator} iterator
* @example
* let map = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* let it = map.find(2);
* it.prev();
* map.erase(it); // removes a node with key 1
* console.log(map.toString()); // {2:B,3:C}
*/
erase(iterator) {
this.__t.erase(iterator.node);
}
/**
* Iterator pointing to the first element that is not less than specified key. If no such element is found, see end() iterator is returned.
* @param {*} key
* @returns {Iterator}
* @example
* let m = new TreeMultiMap();
* ... // add key-value pairs., using numbers as keys
* // iterate through all key-value pairs with keys between 0 and 50 inclusive
* let from = m.lowerBound(0);
* let to = m.upperBound(50);
* let it = from;
* while (!it.equals(to)) {
* console.log(it.key);
* it.next();
* }
*
* let m = new TreeMultiMap();
* ... // add key-value pairs., using numbers as keys
* // iterate through all key-value pairs with keys between 0 and 50 inclusive in reverse order
* let from = new ReverseIterator(m.upperBound(50));
* let to = new ReverseIterator(m.lowerBound(0));
* let it = from;
* while (!it.equals(to)) {
* console.log(it.key);
* it.next();
* }
*/
lowerBound(key) {
return this.__t.lowerBound(key);
}
/**
* Reverse iterator to the last element.
* @returns {ReverseIterator}
* @example
* let m = new TreeMultiMap();
* ...
* for (let it = m.rbegin(); !it.equals(m.rend()); it.next()) {
* console.log(`key: ${it.key}, value: ${it.value}`);
* }
*/
rbegin() {
return this.__t.rbegin();
}
/**
* Reverse iterator pointing to before the first element.
* @returns {ReverseIterator}
* @example
* let m = new TreeMultiMap();
* ...
* for (let it = m.rbegin(); !it.equals(m.rend()); it.next()) {
* console.log(`key: ${it.key}, value: ${it.value}`);
* }
*/
rend() {
return this.__t.rend();
}
/**
* Iterator pointing to the first element that is greater than key. If no such element is found end() iterator is returned.
* @param {*} key
* @returns {Iterator}
* @example
* let m = new TreeMultiMap();
* ... // add key-value pairs., using numbers as keys
* // iterate through all key-value pairs with keys between 0 and 50 inclusive
* let from = m.lowerBound(0);
* let to = m.upperBound(50);
* let it = from;
* while (!it.equals(to)) {
* console.log(it.key);
* it.next();
* }
*
* let m = new TreeMultiMap();
* ... // add key-value pairs., using numbers as keys
* // iterate through all key-value pairs with keys between 0 and 50 inclusive in reverse order
* let from = new ReverseIterator(m.upperBound(50));
* let to = new ReverseIterator(m.lowerBound(0));
* let it = from;
* while (!it.equals(to)) {
* console.log(it.key);
* it.next();
* }
*/
upperBound(key) {
return this.__t.upperBound(key);
}
/**
* @returns first key/value pair of the container, or undefined if container is empty
* @example
* let m = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* let first = m.first();
* if (first) {
* let key = first[0]; // 1
* let value = first[1]; // 'A'
* }
*/
first() {
return this.__t.first();
}
/**
* @returns last key/value pair of the container, or undefined if container is empty
* @example
* let m = new TreeMultiMap([[1, 'A'], [2, 'B'], [3, 'C']]);
* let last = m.last();
* if (last) {
* let key = last[0]; // 3
* let value = last[1]; // 'C'
* }
*/
last() {
return this.__t.last();
}
/**
* Serializes contents of the map in the form {key1:value1,key2:value2,...}
* @returns {String}
*/
toString() {
return this.__t.toString();
}
}
module.exports = {
TreeMultiMap: TreeMultiMap,
};
