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Heap. Javascript & Typescript Data Structure.
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JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Trie = exports.TrieNode = void 0;
const base_1 = require("../base");
/**
* TrieNode represents a node in the Trie data structure. It holds a character key, a map of children nodes,
* and a flag indicating whether it's the end of a word.
*/
class TrieNode {
constructor(key) {
this._key = key;
this._isEnd = false;
this._children = new Map();
}
/**
* The function returns the value of the protected variable _key.
* @returns The value of the `_key` property, which is a string.
*/
get key() {
return this._key;
}
/**
* The above function sets the value of a protected variable called "key".
* @param {string} value - The value parameter is a string that represents the value to be assigned
* to the key.
*/
set key(value) {
this._key = value;
}
/**
* The function returns the children of a TrieNode as a Map.
* @returns The `children` property of the TrieNode object, which is a Map containing string keys and
* TrieNode values.
*/
get children() {
return this._children;
}
/**
* The function sets the value of the `_children` property of a TrieNode object.
* @param value - The value parameter is a Map object that represents the children of a TrieNode. The
* keys of the map are strings, which represent the characters that are associated with each child
* TrieNode. The values of the map are TrieNode objects, which represent the child nodes of the
* current TrieNode.
*/
set children(value) {
this._children = value;
}
/**
* The function returns a boolean value indicating whether a certain condition is met.
* @returns The method is returning a boolean value, specifically the value of the variable `_isEnd`.
*/
get isEnd() {
return this._isEnd;
}
/**
* The function sets the value of the "_isEnd" property.
* @param {boolean} value - The value parameter is a boolean value that indicates whether the current
* state is the end state or not.
*/
set isEnd(value) {
this._isEnd = value;
}
}
exports.TrieNode = TrieNode;
/**
* 1. Node Structure: Each node in a Trie represents a string (or a part of a string). The root node typically represents an empty string.
* 2. Child Node Relationship: Each node's children represent the strings that can be formed by adding one character to the string at the current node. For example, if a node represents the string 'ca', one of its children might represent 'cat'.
* 3. Fast Retrieval: Trie allows retrieval in O(m) time complexity, where m is the length of the string to be searched.
* 4. Space Efficiency: Trie can store a large number of strings very space-efficiently, especially when these strings share common prefixes.
* 5. Autocomplete and Prediction: Trie can be used for implementing autocomplete and word prediction features, as it can quickly find all strings with a common prefix.
* 6. Sorting: Trie can be used to sort a set of strings in alphabetical order.
* 7. String Retrieval: For example, searching for a specific string in a large set of strings.
* 8. Autocomplete: Providing recommended words or phrases as a user types.
* 9. Spell Check: Checking the spelling of words.
* 10. IP Routing: Used in certain types of IP routing algorithms.
* 11. Text Word Frequency Count: Counting and storing the frequency of words in a large amount of text data.
*/
class Trie extends base_1.IterableElementBase {
/**
* The constructor function for the Trie class.
* @param words: Iterable string Initialize the trie with a set of words
* @param options?: TrieOptions Allow the user to pass in options for the trie
* @return This
*/
constructor(words = [], options) {
super(options);
this._size = 0;
this._caseSensitive = true;
this._root = new TrieNode('');
if (options) {
const { caseSensitive } = options;
if (caseSensitive !== undefined)
this._caseSensitive = caseSensitive;
}
if (words) {
for (const word of words) {
if (this.toElementFn) {
this.add(this.toElementFn(word));
}
else {
this.add(word);
}
}
}
}
/**
* The size function returns the size of the stack.
* @return The number of elements in the list
*/
get size() {
return this._size;
}
/**
* The caseSensitive function is a getter that returns the value of the protected _caseSensitive property.
* @return The value of the _caseSensitive protected variable
*/
get caseSensitive() {
return this._caseSensitive;
}
/**
* The root function returns the root node of the tree.
* @return The root node
*/
get root() {
return this._root;
}
/**
* Time Complexity: O(l), where l is the length of the word being added.
* Space Complexity: O(l) - Each character in the word adds a TrieNode.
*
* Add a word to the Trie structure.
* @param {string} word - The word to add.
* @returns {boolean} True if the word was successfully added.
*/
add(word) {
word = this._caseProcess(word);
let cur = this.root;
let isNewWord = false;
for (const c of word) {
let nodeC = cur.children.get(c);
if (!nodeC) {
nodeC = new TrieNode(c);
cur.children.set(c, nodeC);
}
cur = nodeC;
}
if (!cur.isEnd) {
isNewWord = true;
cur.isEnd = true;
this._size++;
}
return isNewWord;
}
/**
* Time Complexity: O(l), where l is the length of the input word.
* Space Complexity: O(1) - Constant space.
*
* Check if the Trie contains a given word.
* @param {string} word - The word to check for.
* @returns {boolean} True if the word is present in the Trie.
*/
has(word) {
word = this._caseProcess(word);
let cur = this.root;
for (const c of word) {
const nodeC = cur.children.get(c);
if (!nodeC)
return false;
cur = nodeC;
}
return cur.isEnd;
}
/**
* Time Complexity: O(1)
* Space Complexity: O(1)
*
* The isEmpty function checks if the size of the queue is 0.
* @return True if the size of the queue is 0
*/
isEmpty() {
return this._size === 0;
}
/**
* Time Complexity: O(1)
* Space Complexity: O(1)
*
* The clear function resets the size of the Trie to 0 and creates a new root TrieNode.
*/
clear() {
this._size = 0;
this._root = new TrieNode('');
}
/**
* Time Complexity: O(l), where l is the length of the word being deleted.
* Space Complexity: O(n) - Due to the recursive DFS approach.
*
* Remove a word from the Trie structure.
* @param{string} word - The word to delete.
* @returns {boolean} True if the word was successfully removed.
*/
delete(word) {
word = this._caseProcess(word);
let isDeleted = false;
const dfs = (cur, i) => {
const char = word[i];
const child = cur.children.get(char);
if (child) {
if (i === word.length - 1) {
if (child.isEnd) {
if (child.children.size > 0) {
child.isEnd = false;
}
else {
cur.children.delete(char);
}
isDeleted = true;
return true;
}
return false;
}
const res = dfs(child, i + 1);
if (res && !cur.isEnd && child.children.size === 0) {
cur.children.delete(char);
return true;
}
return false;
}
return false;
};
dfs(this.root, 0);
if (isDeleted) {
this._size--;
}
return isDeleted;
}
/**
* Time Complexity: O(n), where n is the total number of nodes in the trie.
* Space Complexity: O(1) - Constant space.
*
*/
getHeight() {
const startNode = this.root;
let maxDepth = 0;
if (startNode) {
const bfs = (node, level) => {
if (level > maxDepth) {
maxDepth = level;
}
const { children } = node;
if (children) {
for (const child of children.entries()) {
bfs(child[1], level + 1);
}
}
};
bfs(startNode, 0);
}
return maxDepth;
}
/**
* Time Complexity: O(l), where l is the length of the input prefix.
* Space Complexity: O(1) - Constant space.
*
* Check if a given input string has an absolute prefix in the Trie, meaning it's not a complete word.
* @param {string} input - The input string to check.
* @returns {boolean} True if it's an absolute prefix in the Trie.
*/
hasPurePrefix(input) {
input = this._caseProcess(input);
let cur = this.root;
for (const c of input) {
const nodeC = cur.children.get(c);
if (!nodeC)
return false;
cur = nodeC;
}
return !cur.isEnd;
}
/**
* Time Complexity: O(l), where l is the length of the input prefix.
* Space Complexity: O(1) - Constant space.
*
* Check if a given input string is a prefix of any existing word in the Trie, whether as an absolute prefix or a complete word.
* @param {string} input - The input string representing the prefix to check.
* @returns {boolean} True if it's a prefix in the Trie.
*/
hasPrefix(input) {
input = this._caseProcess(input);
let cur = this.root;
for (const c of input) {
const nodeC = cur.children.get(c);
if (!nodeC)
return false;
cur = nodeC;
}
return true;
}
/**
* Time Complexity: O(n), where n is the total number of nodes in the trie.
* Space Complexity: O(l), where l is the length of the input prefix.
*
* Check if the input string is a common prefix in the Trie, meaning it's a prefix shared by all words in the Trie.
* @param {string} input - The input string representing the common prefix to check for.
* @returns {boolean} True if it's a common prefix in the Trie.
*/
hasCommonPrefix(input) {
input = this._caseProcess(input);
let commonPre = '';
const dfs = (cur) => {
commonPre += cur.key;
if (commonPre === input)
return;
if (cur.isEnd)
return;
if (cur && cur.children && cur.children.size === 1)
dfs(Array.from(cur.children.values())[0]);
else
return;
};
dfs(this.root);
return commonPre === input;
}
/**
* Time Complexity: O(n), where n is the total number of nodes in the trie.
* Space Complexity: O(l), where l is the length of the longest common prefix.
*
* Get the longest common prefix among all the words stored in the Trie.
* @returns {string} The longest common prefix found in the Trie.
*/
getLongestCommonPrefix() {
let commonPre = '';
const dfs = (cur) => {
commonPre += cur.key;
if (cur.isEnd)
return;
if (cur && cur.children && cur.children.size === 1)
dfs(Array.from(cur.children.values())[0]);
else
return;
};
dfs(this.root);
return commonPre;
}
/**
* Time Complexity: O(w * l), where w is the number of words retrieved, and l is the average length of the words.
* Space Complexity: O(w * l) - The space required for the output array.
*
* The `getAll` function returns an array of all words in a Trie data structure that start with a given prefix.
* @param {string} prefix - The `prefix` parameter is a string that represents the prefix that we want to search for in the
* trie. It is an optional parameter, so if no prefix is provided, it will default to an empty string.
* @param {number} max - The max count of words will be found
* @param isAllWhenEmptyPrefix - If true, when the prefix provided as '', returns all the words in the trie.
* @returns {string[]} an array of strings.
*/
getWords(prefix = '', max = Number.MAX_SAFE_INTEGER, isAllWhenEmptyPrefix = false) {
prefix = this._caseProcess(prefix);
const words = [];
let found = 0;
function dfs(node, word) {
for (const char of node.children.keys()) {
const charNode = node.children.get(char);
if (charNode !== undefined) {
dfs(charNode, word.concat(char));
}
}
if (node.isEnd) {
if (found > max - 1)
return;
words.push(word);
found++;
}
}
let startNode = this.root;
if (prefix) {
for (const c of prefix) {
const nodeC = startNode.children.get(c);
if (nodeC) {
startNode = nodeC;
}
else {
// Early return if the whole prefix is not found
return [];
}
}
}
if (isAllWhenEmptyPrefix || startNode !== this.root)
dfs(startNode, prefix);
return words;
}
/**
* Time Complexity: O(n)
* Space Complexity: O(n)
*
* The `clone` function returns a new instance of the Trie class with the same values and case
* sensitivity as the original Trie.
* @returns A new instance of the Trie class is being returned.
*/
clone() {
return new Trie(this, { caseSensitive: this.caseSensitive, toElementFn: this.toElementFn });
}
/**
* Time Complexity: O(n)
* Space Complexity: O(n)
*
* The `filter` function takes a predicate function and returns a new array containing all the
* elements for which the predicate function returns true.
* @param predicate - The `predicate` parameter is a callback function that takes three arguments:
* `word`, `index`, and `this`. It should return a boolean value indicating whether the current
* element should be included in the filtered results or not.
* @param {any} [thisArg] - The `thisArg` parameter is an optional argument that allows you to
* specify the value of `this` within the `predicate` function. It is used when you want to bind a
* specific object as the context for the `predicate` function. If `thisArg` is provided, it will be
* @returns The `filter` method is returning an array of strings (`string[]`).
*/
filter(predicate, thisArg) {
const results = new Trie([], { toElementFn: this.toElementFn, caseSensitive: this.caseSensitive });
let index = 0;
for (const word of this) {
if (predicate.call(thisArg, word, index, this)) {
results.add(word);
}
index++;
}
return results;
}
/**
* Time Complexity: O(n)
* Space Complexity: O(n)
*
* The `map` function creates a new Trie by applying a callback function to each element in the
* current Trie.
* @param callback - The callback parameter is a function that will be called for each element in the
* Trie. It takes four arguments:
* @param [toElementFn] - The `toElementFn` parameter is an optional function that can be used to
* convert the raw element (`RM`) into a string representation. This can be useful if the raw element
* is not already a string or if you want to customize how the element is converted into a string. If
* this parameter is
* @param {any} [thisArg] - The `thisArg` parameter is an optional argument that allows you to
* specify the value of `this` within the callback function. It is used to set the context or scope
* in which the callback function will be executed. If `thisArg` is provided, it will be used as the
* value of
* @returns a new Trie object.
*/
map(callback, toElementFn, thisArg) {
const newTrie = new Trie([], { toElementFn, caseSensitive: this.caseSensitive });
let index = 0;
for (const word of this) {
newTrie.add(callback.call(thisArg, word, index, this));
index++;
}
return newTrie;
}
/**
* Time Complexity: O(n)
* Space Complexity: O(n)
*
* The function `_getIterator` returns an iterable iterator that performs a depth-first search on a
* trie data structure and yields all the paths to the end nodes.
*/
*_getIterator() {
function* _dfs(node, path) {
if (node.isEnd) {
yield path;
}
for (const [char, childNode] of node.children) {
yield* _dfs(childNode, path + char);
}
}
yield* _dfs(this.root, '');
}
/**
* Time Complexity: O(l), where l is the length of the input string.
* Space Complexity: O(1) - Constant space.
*
* @param str
* @protected
*/
_caseProcess(str) {
if (!this._caseSensitive) {
str = str.toLowerCase(); // Convert str to lowercase if case-insensitive
}
return str;
}
}
exports.Trie = Trie;