bintrees

Binary Search Trees

npm install bintrees
27 downloads in the last week
70 downloads in the last month

Binary Trees Build Status

This package provides Binary and Red-Black Search Trees written in Javascript. It is released under the MIT License.

Binary Search Trees are a good way to store data in sorted order. A Red-Black tree is a variation of a Binary Tree that balances itself.

Algorithms were taken from Julienne Walker: http://eternallyconfuzzled.com/jsw_home.aspx

Trees

  • BinTree - Binary Search Tree
  • RBTree - Red-Black Tree

Quickstart

node.js:

npm install bintrees
var Tree = require('bintrees').RBTree;

var tree = new RBTree(function(a, b) { return a - b; });

tree.insert(2);
tree.insert(-3);

see examples/node.js for more info

In the browser:

<script src="/path/to/rbtree.js"></script>
<script>
    var tree = new RBTree(function(a, b) { return a - b; });
    tree.insert(0);
    tree.insert(1);
</script>

see examples/client.html for more info

Constructor

Requires 1 argument: a comparator function f(a,b) which returns:

  • 0 if a == b
  • 0 if a > b

  • <0 if a < b

Methods

insert(item)

Inserts the item into the tree. Returns true if inserted, false if duplicate.

remove(item)

Removes the item from the tree. Returns true if removed, false if not found.

size

Number of nodes in the tree.

clear()

Removes all nodes from the tree.

find(item)

Returns node data if found, null otherwise.

findIter(item)

Returns an iterator to the node if found, null otherwise.

lowerBound(item)

Returns an interator to the tree node at or immediately after the item. Returns null-iterator if tree is empty.

NOTE: Changed in version 1.0.0 to match C++ lower_bound

upperBound(item)

Returns an interator to the tree node immediately after the item. Returns null-iterator if tree is empty.

NOTE: Changed in version 1.0.0 to match C++ upper_bound

min()

Returns the min node data in the tree, or null if the tree is empty.

max()

Returns the max node data in the tree, or null if the tree is empty.

each(f)

Calls f on each node's data, in order.

reach(f)

Calls f on each node's data, in reverse order.

iterator()

Returns a null-iterator. See Iterators section below.

Iterators

tree.iterator() will return a null-iterator. On a null iterator,

  • next() will return the first element in the tree
  • prev() will return the last element in the tree

Otherwise,

  • next() will return the next element
  • prev() will return the previous element

When iteration reaches the end, the iterator becomes a null-iterator again.

Forward iteration example:

var it=tree.iterator(), item;
while((item = it.next()) !== null) {
    // do stuff with item
}

If you are iterating forward through the tree, you can always call prev() to go back, and vice versa.

NOTE: iterators become invalid when you add or remove elements from the tree.

npm loves you