/**
* Created by Alex Bol on 3/31/2017.
*/
'use strict';
import Node from './node.js';
import {RB_TREE_COLOR_RED, RB_TREE_COLOR_BLACK} from '../utils/constants.js';
// const nil_node = new Node();
/**
* Implementation of interval binary search tree <br/>
* Interval tree stores items which are couples of {key:interval, value: value} <br/>
* Interval is an object with high and low properties or simply pair [low,high] of numeric values <br />
* @type {IntervalTree}
*/
class IntervalTree {
/**
* Construct new empty instance of IntervalTree
*/
constructor() {
this.root = null;
this.nil_node = new Node();
}
/**
* Returns number of items stored in the interval tree
* @returns {number}
*/
get size() {
let count = 0;
this.tree_walk(this.root, () => count++);
return count;
}
/**
* Returns array of sorted keys in the ascending order
* @returns {Array}
*/
get keys() {
let res = [];
this.tree_walk(this.root, (node) => res.push(
node.item.key.output ? node.item.key.output() : node.item.key
));
return res;
}
/**
* Return array of values in the ascending keys order
* @returns {Array}
*/
get values() {
let res = [];
this.tree_walk(this.root, (node) => res.push(node.item.value));
return res;
}
/**
* Returns array of items (<key,value> pairs) in the ascended keys order
* @returns {Array}
*/
get items() {
let res = [];
this.tree_walk(this.root, (node) => res.push({
key: node.item.key.output ? node.item.key.output() : node.item.key,
value: node.item.value
}));
return res;
}
/**
* Returns true if tree is empty
* @returns {boolean}
*/
isEmpty() {
return (this.root == null || this.root == this.nil_node);
}
/**
* Clear tree
*/
clear() {
this.root = null
}
/**
* Insert new item into interval tree
* @param {Interval} key - interval object or array of two numbers [low, high]
* @param {any} value - value representing any object (optional)
* @returns {Node} returns reference to inserted node as an object {key:interval, value: value}
*/
insert(key, value = key) {
if (key === undefined) return;
let insert_node = new Node(key, value, this.nil_node, this.nil_node, null, RB_TREE_COLOR_RED);
this.tree_insert(insert_node);
this.recalc_max(insert_node);
return insert_node;
}
/**
* Returns true if item {key,value} exist in the tree
* @param {Interval} key - interval correspondent to keys stored in the tree
* @param {any} value - value object to be checked
* @returns {boolean} true if item {key, value} exist in the tree, false otherwise
*/
exist(key, value = key) {
let search_node = new Node(key, value);
return this.tree_search(this.root, search_node) ? true : false;
}
/**
* Remove entry {key, value} from the tree
* @param {Interval} key - interval correspondent to keys stored in the tree
* @param {any} value - value object
* @returns {boolean} true if item {key, value} deleted, false if not found
*/
remove(key, value = key) {
let search_node = new Node(key, value);
let delete_node = this.tree_search(this.root, search_node);
if (delete_node) {
this.tree_delete(delete_node);
}
return delete_node;
}
/**
* Returns array of entry values which keys intersect with given interval <br/>
* If no values stored in the tree, returns array of keys which intersect given interval
* @param {Interval} interval - search interval, or tuple [low, high]
* @param outputMapperFn(value,key) - optional function that maps (value, key) to custom output
* @returns {Array}
*/
search(interval, outputMapperFn = (value, key) => value === key ? key.output() : value) {
let search_node = new Node(interval);
let resp_nodes = [];
this.tree_search_interval(this.root, search_node, resp_nodes);
return resp_nodes.map(node => outputMapperFn(node.item.value, node.item.key))
}
/**
* Returns true if intersection between given and any interval stored in the tree found
* @param {Interval} interval - search interval or tuple [low, high]
* @returns {boolean}
*/
intersect_any(interval) {
let search_node = new Node(interval);
let found = this.tree_find_any_interval(this.root, search_node);
return found;
}
/**
* Tree visitor. For each node implement a callback function. <br/>
* Method calls a callback function with two parameters (key, value)
* @param visitor(key,value) - function to be called for each tree item
*/
forEach(visitor) {
this.tree_walk(this.root, (node) => visitor(node.item.key, node.item.value));
}
/**
* Value Mapper. Walk through every node and map node value to another value
* @param callback(value,key) - function to be called for each tree item
*/
map(callback) {
const tree = new IntervalTree();
this.tree_walk(this.root, (node) => tree.insert(node.item.key, callback(node.item.value, node.item.key)));
return tree;
}
/**
* @param {Interval} interval - optional if the iterator is intended to start from the beginning
* @param outputMapperFn(value,key) - optional function that maps (value, key) to custom output
* @returns {Iterator}
*/
*iterate(interval, outputMapperFn = (value, key) => value === key ? key.output() : value) {
let node;
if (interval) {
node = this.tree_search_nearest_forward(this.root, new Node(interval));
} else if (this.root) {
node = this.local_minimum(this.root);
}
while (node) {
yield outputMapperFn(node.item.value, node.item.key);
node = this.tree_successor(node);
}
}
recalc_max(node) {
let node_current = node;
while (node_current.parent != null) {
node_current.parent.update_max();
node_current = node_current.parent;
}
}
tree_insert(insert_node) {
let current_node = this.root;
let parent_node = null;
if (this.root == null || this.root == this.nil_node) {
this.root = insert_node;
}
else {
while (current_node != this.nil_node) {
parent_node = current_node;
if (insert_node.less_than(current_node)) {
current_node = current_node.left;
}
else {
current_node = current_node.right;
}
}
insert_node.parent = parent_node;
if (insert_node.less_than(parent_node)) {
parent_node.left = insert_node;
}
else {
parent_node.right = insert_node;
}
}
this.insert_fixup(insert_node);
}
// After insertion insert_node may have red-colored parent, and this is a single possible violation
// Go upwords to the root and re-color until violation will be resolved
insert_fixup(insert_node) {
let current_node;
let uncle_node;
current_node = insert_node;
while (current_node != this.root && current_node.parent.color == RB_TREE_COLOR_RED) {
if (current_node.parent == current_node.parent.parent.left) { // parent is left child of grandfather
uncle_node = current_node.parent.parent.right; // right brother of parent
if (uncle_node.color == RB_TREE_COLOR_RED) { // Case 1. Uncle is red
// re-color father and uncle into black
current_node.parent.color = RB_TREE_COLOR_BLACK;
uncle_node.color = RB_TREE_COLOR_BLACK;
current_node.parent.parent.color = RB_TREE_COLOR_RED;
current_node = current_node.parent.parent;
}
else { // Case 2 & 3. Uncle is black
if (current_node == current_node.parent.right) { // Case 2. Current if right child
// This case is transformed into Case 3.
current_node = current_node.parent;
this.rotate_left(current_node);
}
current_node.parent.color = RB_TREE_COLOR_BLACK; // Case 3. Current is left child.
// Re-color father and grandfather, rotate grandfather right
current_node.parent.parent.color = RB_TREE_COLOR_RED;
this.rotate_right(current_node.parent.parent);
}
}
else { // parent is right child of grandfather
uncle_node = current_node.parent.parent.left; // left brother of parent
if (uncle_node.color == RB_TREE_COLOR_RED) { // Case 4. Uncle is red
// re-color father and uncle into black
current_node.parent.color = RB_TREE_COLOR_BLACK;
uncle_node.color = RB_TREE_COLOR_BLACK;
current_node.parent.parent.color = RB_TREE_COLOR_RED;
current_node = current_node.parent.parent;
}
else {
if (current_node == current_node.parent.left) { // Case 5. Current is left child
// Transform into case 6
current_node = current_node.parent;
this.rotate_right(current_node);
}
current_node.parent.color = RB_TREE_COLOR_BLACK; // Case 6. Current is right child.
// Re-color father and grandfather, rotate grandfather left
current_node.parent.parent.color = RB_TREE_COLOR_RED;
this.rotate_left(current_node.parent.parent);
}
}
}
this.root.color = RB_TREE_COLOR_BLACK;
}
tree_delete(delete_node) {
let cut_node; // node to be cut - either delete_node or successor_node ("y" from 14.4)
let fix_node; // node to fix rb tree property ("x" from 14.4)
if (delete_node.left == this.nil_node || delete_node.right == this.nil_node) { // delete_node has less then 2 children
cut_node = delete_node;
}
else { // delete_node has 2 children
cut_node = this.tree_successor(delete_node);
}
// fix_node if single child of cut_node
if (cut_node.left != this.nil_node) {
fix_node = cut_node.left;
}
else {
fix_node = cut_node.right;
}
// remove cut_node from parent
/*if (fix_node != this.nil_node) {*/
fix_node.parent = cut_node.parent;
/*}*/
if (cut_node == this.root) {
this.root = fix_node;
}
else {
if (cut_node == cut_node.parent.left) {
cut_node.parent.left = fix_node;
}
else {
cut_node.parent.right = fix_node;
}
cut_node.parent.update_max(); // update max property of the parent
}
this.recalc_max(fix_node); // update max property upward from fix_node to root
// COPY DATA !!!
// Delete_node becomes cut_node, it means that we cannot hold reference
// to node in outer structure and we will have to delete by key, additional search need
if (cut_node != delete_node) {
delete_node.copy_data(cut_node);
delete_node.update_max(); // update max property of the cut node at the new place
this.recalc_max(delete_node); // update max property upward from delete_node to root
}
if (/*fix_node != this.nil_node && */cut_node.color == RB_TREE_COLOR_BLACK) {
this.delete_fixup(fix_node);
}
}
delete_fixup(fix_node) {
let current_node = fix_node;
let brother_node;
while (current_node != this.root && current_node.parent != null && current_node.color == RB_TREE_COLOR_BLACK) {
if (current_node == current_node.parent.left) { // fix node is left child
brother_node = current_node.parent.right;
if (brother_node.color == RB_TREE_COLOR_RED) { // Case 1. Brother is red
brother_node.color = RB_TREE_COLOR_BLACK; // re-color brother
current_node.parent.color = RB_TREE_COLOR_RED; // re-color father
this.rotate_left(current_node.parent);
brother_node = current_node.parent.right; // update brother
}
// Derive to cases 2..4: brother is black
if (brother_node.left.color == RB_TREE_COLOR_BLACK &&
brother_node.right.color == RB_TREE_COLOR_BLACK) { // case 2: both nephews black
brother_node.color = RB_TREE_COLOR_RED; // re-color brother
current_node = current_node.parent; // continue iteration
}
else {
if (brother_node.right.color == RB_TREE_COLOR_BLACK) { // case 3: left nephew red, right nephew black
brother_node.color = RB_TREE_COLOR_RED; // re-color brother
brother_node.left.color = RB_TREE_COLOR_BLACK; // re-color nephew
this.rotate_right(brother_node);
brother_node = current_node.parent.right; // update brother
// Derive to case 4: left nephew black, right nephew red
}
// case 4: left nephew black, right nephew red
brother_node.color = current_node.parent.color;
current_node.parent.color = RB_TREE_COLOR_BLACK;
brother_node.right.color = RB_TREE_COLOR_BLACK;
this.rotate_left(current_node.parent);
current_node = this.root; // exit from loop
}
}
else { // fix node is right child
brother_node = current_node.parent.left;
if (brother_node.color == RB_TREE_COLOR_RED) { // Case 1. Brother is red
brother_node.color = RB_TREE_COLOR_BLACK; // re-color brother
current_node.parent.color = RB_TREE_COLOR_RED; // re-color father
this.rotate_right(current_node.parent);
brother_node = current_node.parent.left; // update brother
}
// Go to cases 2..4
if (brother_node.left.color == RB_TREE_COLOR_BLACK &&
brother_node.right.color == RB_TREE_COLOR_BLACK) { // case 2
brother_node.color = RB_TREE_COLOR_RED; // re-color brother
current_node = current_node.parent; // continue iteration
}
else {
if (brother_node.left.color == RB_TREE_COLOR_BLACK) { // case 3: right nephew red, left nephew black
brother_node.color = RB_TREE_COLOR_RED; // re-color brother
brother_node.right.color = RB_TREE_COLOR_BLACK; // re-color nephew
this.rotate_left(brother_node);
brother_node = current_node.parent.left; // update brother
// Derive to case 4: right nephew black, left nephew red
}
// case 4: right nephew black, left nephew red
brother_node.color = current_node.parent.color;
current_node.parent.color = RB_TREE_COLOR_BLACK;
brother_node.left.color = RB_TREE_COLOR_BLACK;
this.rotate_right(current_node.parent);
current_node = this.root; // force exit from loop
}
}
}
current_node.color = RB_TREE_COLOR_BLACK;
}
tree_search(node, search_node) {
if (node == null || node == this.nil_node)
return undefined;
if (search_node.equal_to(node)) {
return node;
}
if (search_node.less_than(node)) {
return this.tree_search(node.left, search_node);
}
else {
return this.tree_search(node.right, search_node);
}
}
tree_search_nearest_forward(node, search_node) {
let best;
let curr = node;
while (curr && curr != this.nil_node) {
if (curr.less_than(search_node)) {
if (curr.intersect(search_node) && (!best || curr.less_than(best))) best = curr;
curr = curr.right;
} else {
if (!best || curr.less_than(best)) best = curr;
curr = curr.left;
}
}
return best || null;
}
// Original search_interval method; container res support push() insertion
// Search all intervals intersecting given one
tree_search_interval(node, search_node, res) {
if (node != null && node != this.nil_node) {
// if (node->left != this.nil_node && node->left->max >= low) {
if (node.left != this.nil_node && !node.not_intersect_left_subtree(search_node)) {
this.tree_search_interval(node.left, search_node, res);
}
// if (low <= node->high && node->low <= high) {
if (node.intersect(search_node)) {
res.push(node);
}
// if (node->right != this.nil_node && node->low <= high) {
if (node.right != this.nil_node && !node.not_intersect_right_subtree(search_node)) {
this.tree_search_interval(node.right, search_node, res);
}
}
}
tree_find_any_interval(node, search_node) {
let found = false;
if (node != null && node != this.nil_node) {
// if (node->left != this.nil_node && node->left->max >= low) {
if (node.left != this.nil_node && !node.not_intersect_left_subtree(search_node)) {
found = this.tree_find_any_interval(node.left, search_node);
}
// if (low <= node->high && node->low <= high) {
if (!found) {
found = node.intersect(search_node);
}
// if (node->right != this.nil_node && node->low <= high) {
if (!found && node.right != this.nil_node && !node.not_intersect_right_subtree(search_node)) {
found = this.tree_find_any_interval(node.right, search_node);
}
}
return found;
}
local_minimum(node) {
let node_min = node;
while (node_min.left != null && node_min.left != this.nil_node) {
node_min = node_min.left;
}
return node_min;
}
// not in use
local_maximum(node) {
let node_max = node;
while (node_max.right != null && node_max.right != this.nil_node) {
node_max = node_max.right;
}
return node_max;
}
tree_successor(node) {
let node_successor;
let current_node;
let parent_node;
if (node.right != this.nil_node) {
node_successor = this.local_minimum(node.right);
}
else {
current_node = node;
parent_node = node.parent;
while (parent_node != null && parent_node.right == current_node) {
current_node = parent_node;
parent_node = parent_node.parent;
}
node_successor = parent_node;
}
return node_successor;
}
// | right-rotate(T,y) |
// y ---------------. x
// / \ / \
// x c left-rotate(T,x) a y
// / \ <--------------- / \
// a b b c
rotate_left(x) {
let y = x.right;
x.right = y.left; // b goes to x.right
if (y.left != this.nil_node) {
y.left.parent = x; // x becomes parent of b
}
y.parent = x.parent; // move parent
if (x == this.root) {
this.root = y; // y becomes root
}
else { // y becomes child of x.parent
if (x == x.parent.left) {
x.parent.left = y;
}
else {
x.parent.right = y;
}
}
y.left = x; // x becomes left child of y
x.parent = y; // and y becomes parent of x
if (x != null && x != this.nil_node) {
x.update_max();
}
y = x.parent;
if (y != null && y != this.nil_node) {
y.update_max();
}
}
rotate_right(y) {
let x = y.left;
y.left = x.right; // b goes to y.left
if (x.right != this.nil_node) {
x.right.parent = y; // y becomes parent of b
}
x.parent = y.parent; // move parent
if (y == this.root) { // x becomes root
this.root = x;
}
else { // y becomes child of x.parent
if (y == y.parent.left) {
y.parent.left = x;
}
else {
y.parent.right = x;
}
}
x.right = y; // y becomes right child of x
y.parent = x; // and x becomes parent of y
if (y != null && y != this.nil_node) {
y.update_max();
}
x = y.parent;
if (x != null && x != this.nil_node) {
x.update_max();
}
}
tree_walk(node, action) {
if (node != null && node != this.nil_node) {
this.tree_walk(node.left, action);
// arr.push(node.toArray());
action(node);
this.tree_walk(node.right, action);
}
}
/* Return true if all red nodes have exactly two black child nodes */
testRedBlackProperty() {
let res = true;
this.tree_walk(this.root, function (node) {
if (node.color == RB_TREE_COLOR_RED) {
if (!(node.left.color == RB_TREE_COLOR_BLACK && node.right.color == RB_TREE_COLOR_BLACK)) {
res = false;
}
}
});
return res;
}
/* Throw error if not every path from root to bottom has same black height */
testBlackHeightProperty(node) {
let height = 0;
let heightLeft = 0;
let heightRight = 0;
if (node.color == RB_TREE_COLOR_BLACK) {
height++;
}
if (node.left != this.nil_node) {
heightLeft = this.testBlackHeightProperty(node.left);
}
else {
heightLeft = 1;
}
if (node.right != this.nil_node) {
heightRight = this.testBlackHeightProperty(node.right);
}
else {
heightRight = 1;
}
if (heightLeft != heightRight) {
throw new Error('Red-black height property violated');
}
height += heightLeft;
return height;
}
};
export default IntervalTree;