giancucinotta / binary-search-tree

Binary Search Tree & AVL Tree (Self Balancing Tree) implementation in javascript.

@datastructures-js/binary-search-tree

Binary Search Tree & AVL Tree (Self Balancing Tree) implementation in javascript.

Binary Search Tree
AVL Tree (Self Balancing Tree)

Table of Contents

• Install
• API
  • require
  • import
  • new
  • .insert(key, value)
  • .has(key)
  • .find(key)
  • .min()
  • .max()
  • .lowerBound(k)
  • .upperBound(k)
  • .root()
  • .count()
  • .traverseInOrder(cb)
  • .traversePreOrder(cb)
  • .traversePostOrder(cb)
  • .remove(key)
  • .clear()
  • BinarySearchTreeNode
  • AvlTreeNode
• Build
• License

install

npm install --save @datastructures-js/binary-search-tree

API

require

const {
  BinarySearchTree,
  BinarySearchTreeNode,
  AvlTree,
  AvlTreeNode
} = require('@datastructures-js/binary-search-tree');

import

import {
  BinarySearchTree,
  BinarySearchTreeNode,
  AvlTree,
  AvlTreeNode
} from '@datastructures-js/binary-search-tree';

new

const bst = new BinarySearchTree();

// self balancing tree
const bst = new AvlTree();

.insert(key, value)

inserts a node with key/value into the tree and returns the inserted node. Inserting an node with existing key, will update the existing node's value with the new one.

params	return	runtime
key: number | string value: any	BinarySearchTreeNode | AvlTreeNode	O(log(n))

bst.insert(50, 'v1');
bst.insert(80, 'v2');
bst.insert(30, 'v3');
bst.insert(90, 'v4');
bst.insert(60, 'v5');
bst.insert(40, 'v6');
bst.insert(20, 'v7');

.has(key)

checks if a node exists by its key.

params	return	runtime
key: number | string	boolean	O(log(n))

bst.has(50); // true
bst.has(100); // false

.find(key)

finds a node in the tree by its key.

params	return	runtime
key: number | string	BinarySearchTreeNode | AvlTreeNode	O(log(n))

const n60 = bst.find(60);
console.log(n60.getKey()); // 60
console.log(n60.getValue()); // v5

console.log(bst.find(100)); // null

.min()

finds the node with min key in the tree.

return	runtime
BinarySearchTreeNode | AvlTreeNode	O(log(n))

const min = bst.min();
console.log(min.getKey()); // 20
console.log(min.getValue()); // v7

.max()

finds the node with max key in the tree.

return	runtime
BinarySearchTreeNode | AvlTreeNode	O(log(n))

const max = bst.max();
console.log(max.getKey()); // 90
console.log(max.getValue()); // v4

.lowerBound(k)

finds the node with the biggest key less or equal a given value k.

params	return	runtime
k: number | string	BinarySearchTreeNode | AvlTreeNode	O(log(n))

console.log(bst.lowerBound(60).getKey()); // 50
console.log(bst.lowerBound(10)); // null

.upperBound(k)

finds the node with the smallest key bigger than a given value k.

params	return	runtime
k: number | string	BinarySearchTreeNode | AvlTreeNode	O(log(n))

console.log(bst.upperBound(75).getKey()); // 80
console.log(bst.upperBound(110)); // null

.root()

returns the root node of the tree.

return	runtime
BinarySearchTreeNode | AvlTreeNode	O(1)

const root = bst.root();
console.log(root.getKey()); // 50
console.log(root.getValue()); // v1

.count()

returns the count of nodes in the tree.

return	runtime
number	O(1)

console.log(bst.count()); // 7

.traverseInOrder(cb)

traverses the tree in order (left-node-right).

params	runtime
cb: function	O(n)

bst.traverseInOrder((node) => console.log(node.getKey()));

/*
  20
  30
  40
  50
  60
  80
  90
*/

.traversePreOrder(cb)

traverses the tree pre order (node-left-right).

params	runtime
cb: function	O(n)

bst.traversePreOrder((node) => console.log(node.getKey()));

/*
  50
  30
  20
  40
  80
  60
  90
*/

.traversePostOrder(cb)

traverses the tree post order (left-right-node).

params	runtime
cb: function	O(n)

bst.traversePostOrder((node) => console.log(node.getKey()));

/*
  20
  40
  30
  60
  90
  80
  50
*/

.remove(key)

removes a node from the tree by its key. AVL tree will rotate nodes properly if the tree becomes unbalanced during deletion.

params	return	runtime
key: number | string	boolean	O(log(n))

bst.remove(20); // true
bst.remove(100); // false
console.log(bst.count()); // 6

.clear()

clears the tree.

runtime
O(1)

bst.clear();
console.log(bst.count()); // 0
console.log(bst.root()); // null

BinarySearchTreeNode

.getKey()

return
number | string

.setValue(value)

params
value: any

.getValue()

return
any

.setLeft(left)

params
left: BinarySearchTreeNode | null

.getLeft()

return
BinarySearchTreeNode | null

.hasLeft()

return
boolean

.setRight(right)

params
right: BinarySearchTreeNode | null

.getRight()

return
BinarySearchTreeNode | null

.hasRight()

return
boolean

.setParent(parent)

params
parent: BinarySearchTreeNode | null

.getParent()

return
BinarySearchTreeNode | null

.hasParent()

return
boolean

.isLeaf()

return
boolean

.isRoot()

return
boolean

AvlTreeNode

extends BinarySearchTreeNode and adds the following methods:

.rotateLeft()

Rotates self left (counter-clockwise).

return
AvlTreeNode

.rotateRight()

Rotates self right (clockwise).

return
AvlTreeNode

.rotateLeftRight()

Rotates left child to left then self to right.

return
AvlTreeNode

.rotateRightLeft()

Rotates right child to right then self to left.

return
AvlTreeNode

.getHeight()

Gets the height of the node in the tree. root height is 1.

return
number

.getLeftHeight()

Gets the height of left child. 0 if no left child.

return
number

.getRightHeight()

Gets the height of right child. 0 if no right child.

return
number

.getBalance()

returns the node's balance as the diff between left and right heights.

return
number

.isBalanced()

checks if the node is balanced. (height diff is not more/less than 1/-1)

return
boolean

Build

grunt build

License

The MIT License. Full License is here