Mnemonist

Suffix Array


A suffix array is the array of a string’s possible suffixes stored in lexicographical order.

For instance, the string banana has the following suffixes:

banana
anana
nana
ana
na
a

So, in lexicographical order, the suffixes would be stored likewise:

a
ana
anana
banana
na
nana

Which is encoded by the following array if we refer to each suffix by its starting index:

[5, 3, 1, 0, 4, 2]

But the real purpose of mnemonist’s SuffixArray class is that it uses Karkkainen and Sanders’ algorithm to build the array in linear time, whereas a naive implementation would do it in quadratic time.

For more information about the Suffix Array, you can head here.

var SuffixArray = require('mnemonist/suffix-array');

Constructor

The SuffixArray class simply takes a single string or arbitrary array of string tokens as its only argument:

var suffixArray = new SuffixArray('banana');

// Also works with arbitrary sequences of tokens
var suffixArray = new SuffixArray(['the', 'cat', 'eats', 'the', 'mouse']);

Note that if you pass an arbitrary array of tokens, computation time for the suffix array is approximately O(n log n), which is obviously slower than for a simple string.

Members

#.array

The computed suffix array.

var suffixArray = new SuffixArray('banana');
suffixArray.array
>>> [5, 3, 1, 0, 4, 2]

#.length

The length of the array.

var suffixArray = new SuffixArray('banana');
suffixArray.length
>>> 6

#.string

The stored string.

var suffixArray = new SuffixArray('banana');
suffixArray.string
>>> 'banana'