lgrthms/lib/dataStructures/Trie.js

Algorithms and data structures for your JavaScript and TypeScript projects 🧑‍💻

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Trie = void 0;
class Trie {
    constructor() {
        this.root = {};
        this.endSymbol = '***';
        this._size = 0;
    }
    get size() {
        return this._size;
    }
    // O(n) time | O(n) space — where n is is the length of the string
    insert(string) {
        let node = this.root;
        for (const char of string) {
            if (node[char] === undefined) {
                node[char] = {};
            }
            node = node[char];
        }
        node[this.endSymbol] = string;
        this._size++;
        return this._size;
    }
    // O(n) time | O(1) space — where n is is the length of the string
    contains(string) {
        let node = this.root;
        for (const char of string) {
            if (node[char] === undefined) {
                return false;
            }
            node = node[char];
        }
        return node[this.endSymbol] !== undefined;
    }
    // O(n) time | O(n space) — where n is is the length of the string
    remove(string) {
        this._remove(string, 0, this.root);
    }
    // O(m) time | O(n) space — where
    // m is the total number of characters in the trie
    // n is the length of the longest word
    autocomplete(string, limit = Infinity) {
        let node = this.root;
        for (const char of string) {
            if (node[char] === undefined) {
                return [];
            }
            node = node[char];
        }
        return this._getWords(node, [], limit);
    }
    // O(m) time | O(n) space — where
    // m is the total number of characters in the trie
    // n is the length of the longest word
    getWords() {
        return this._getWords(this.root, [], Infinity);
    }
    _remove(string, index, node) {
        if (index === string.length) {
            if (node[this.endSymbol] === undefined) {
                return false;
            }
            delete node[this.endSymbol];
            this._size--;
            return Object.keys(node).length === 0;
        }
        const char = string[index];
        if (node[char] === undefined) {
            return false;
        }
        const canRemove = this._remove(string, index + 1, node[char]);
        if (canRemove) {
            delete node[char];
        }
        return Object.keys(node).length === 0;
    }
    _getWords(node, array, limit) {
        for (const char in node) {
            if (array.length === limit) {
                break;
            }
            if (char === this.endSymbol) {
                array.push(node[this.endSymbol]);
                continue;
            }
            this._getWords(node[char], array, limit);
        }
        return array;
    }
}
exports.Trie = Trie;