73 lines
1.9 KiB
JavaScript
73 lines
1.9 KiB
JavaScript
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(function (exports) {
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'use strict';
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function Node(val) {
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this.value = val;
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this.nodes = {};
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}
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function SuffixTree() {
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this.root = new Node();
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}
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SuffixTree.prototype.addNode = (function () {
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function maxPrefix(a, b) {
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var res = [];
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for (var i = 0; i < Math.min(a.length, b.length); i += 1) {
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if (a[i] === b[i]) {
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res.push(a[i]);
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} else {
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return '';
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}
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}
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return res.join('');
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}
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function addNode(suffix, current) {
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// Empty string already exists in the suffix tree
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if (!suffix) {
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return;
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}
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// The suffix is already inside the tree
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if (current.value === suffix) {
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return;
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}
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// Insert recursively
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if (current.nodes[suffix[0]]) {
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return addNode(suffix.substr(1, suffix.length),
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current.nodes[suffix[0]]);
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}
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// Find the maximum prefix and split the current node if prefix exists
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var prefix = maxPrefix(current.value, suffix);
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if (prefix.length) {
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var temp = current.value;
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var suffixSuffix = suffix.substr(prefix.length, suffix.length);
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var currentSuffix = temp.substr(prefix.length, temp.length);
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current.value = prefix;
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addNode(currentSuffix, current);
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addNode(suffixSuffix, current);
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// If prefix doesn't exists add new child node
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} else {
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current.nodes[suffix[0]] = new Node(suffix);
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}
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}
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return function (suffix) {
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addNode(suffix, this.root);
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};
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}());
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// O(n^2) or even O(n^3) because of maxPrefix
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SuffixTree.prototype.build = function (string) {
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this.root.value = string;
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for (var i = 1; i < string.length; i += 1) {
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this.addNode(string.substr(i, string.length));
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}
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};
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exports.Node = Node;
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exports.SuffixTree = SuffixTree;
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}(typeof exports === 'undefined' ? window : exports));
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