trie-contact.ts

class TNode {
  letter: string;
  num: number;
  children: { [letter: string]: TNode };
  constructor(letter: string) {
    this.letter = letter;
    this.num = 1;
    this.children = {};
  }
}

class Trie {
  root: TNode;
  constructor() {
    this.root = new TNode("");
  }
  add(name: string) {
    let current = this.root;
    current.num += 1;
    for (let i = 0; i < name.length; i++) {
      const char = name[i];
      if (typeof current.children[char] === "undefined") {
        current.children[char] = new TNode(char);
        current = current.children[char];
      } else {
        current = current.children[char];
        current.num += 1;
      }
    }
  }
  find(name: string): number {
    let current = this.root;
    for (let i = 0; i < name.length; i++) {
      const char = name[i];
      if (typeof current.children[char] === "undefined") {
        return 0;
      } else {
        current = current.children[char];
      }
    }
    return current.num;
  }
}

function contacts(queries: string[][]): number[] {
  // Write your code here
  // - Add the responses to `ans` array
  // Make a trie
  // - class TNode
  // Add name
  // Iterate over each char of `name`
  // current = root
  // current.num += 1
  // for char of name:
  //   if current.children[char] is undefined:
  //     # Create a new node!
  //     current.children[char] = new TNode(char);
  //     current = current.children[char]
  //   else:
  //     current = current.children[char]
  //     current.num += 1
  const trie = new Trie();
  const ans: number[] = [];
  for (const query of queries) {
    switch (query[0]) {
      case "add":
        trie.add(query[1]);
        break;
      case "find":
        const num = trie.find(query[1]);
        ans.push(num);
        break;
    }
  }
  return ans;
}