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Binary Indexed Tree

Binary Indexed Tree(aka Fenwick Tree) implementation

Install

Install with npm:

$ npm install binary-indexed-tree

BIT?

Binary Indexed Tree (aka Fenwick Tree) is a data structure providing efficient methods for prefix-sum.

API

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Table of Contents

BinaryIndexedTree

BinaryIndexedTree implementation

Parameters

length

Type: number

Returns number size of BIT

add

Parameters

Returns boolean successfully added or not O(log(N))

update

Parameters

Returns boolean successfully updated or not O(log(N))

original

Parameters

Returns number original value of array O(log(N))

get

Parameters

Returns number sum of range [0..idx] O(log(N))

prefix

Parameters

Returns number sum of range [0..idx) O(log(N))

sum

Returns number sum of all O(log(N))

find

linear search.

Parameters

Returns number value of first target, or undefined O(N * log(N))

findIndex

linear search.

Parameters

Returns number index of first target, or -1 O(N * log(N))

indexOf

linear search.

Parameters

Returns number index of first target, or -1 O(N * log(N))

lastIndexOf

linear search.

Parameters

Returns number index of last target, or -1 O(N * log(N))

lowerBound

find lower bound. SEQUENCE MUST BE STRICTLY SORTED.

Parameters

Returns number index of lower-bound O(log(N))

upperBound

find upper bound. SEQUENCE MUST BE STRICTLY SORTED.

Parameters

Returns number index of upper-bound O(log(N))

toArray

Returns Array<number> array of cusum O(N)

build

Parameters

Returns BinaryIndexedTree instance O(N)

Changelog

Read the CHANGELOG.

Running tests

Install devDependencies and Run npm test:

$ npm -d it

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

  1. Fork it!
  2. Create your feature branch: git checkout -b my-new-feature
  3. Commit your changes: git commit -am 'Add some feature'
  4. Push to the branch: git push origin my-new-feature
  5. Submit a pull request :D

License

Copyright © 2016-present berlysia. Licensed under the MIT license.