# bintrees

Binary Search Trees

``npm install bintrees``

# Binary Trees

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);
``````

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>
``````

## 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.

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