1032.字符流.js

/*
 * @lc app=leetcode.cn id=1032 lang=javascript
 *
 * [1032] 字符流
 */

// @lc code=start
/**
 * @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)
 */
// @lc code=end