1032_stream-of-characters.js

/**
 * Title: Stream of Characters
 * Description: Design an algorithm that accepts a stream of characters and checks if a suffix of these characters is a string of a given array of strings words.
 * Author: Hasibul Islam
 * Date: 28/04/2023
 */

/**
 * @param {string[]} words
 */
var StreamChecker = function (words) {
  this.root = {};
  for (let w of words) {
    w = w.split("").reverse().join("");
    let node = this.root;
    for (let c of w) {
      if (!node[c]) node[c] = {};
      node = node[c];
    }
    node.word = w;
  }
  this.letters = [];
};

/**
 * @param {character} letter
 * @return {boolean}
 */
StreamChecker.prototype.query = function (letter) {
  this.letters.push(letter);
  let lookingIn = this.root;
  for (let i = this.letters.length - 1; i >= 0; i--) {
    if (lookingIn[this.letters[i]]) {
      lookingIn = lookingIn[this.letters[i]];
      if (lookingIn.word) return true;
    } else {
      return false;
    }
  }
  return false;
};

/**
 * Your StreamChecker object will be instantiated and called as such:
 * var obj = new StreamChecker(words)
 * var param_1 = obj.query(letter)
 */