Node.js) 백준 17071: 숨바꼭질 5

https://www.acmicpc.net/problem/17071

17071번: 숨바꼭질 5

class Node {
  constructor(item) {
    this.item = item;
    this.next = null;
  }
}

class Queue {
  constructor() {
    this.head = null;
    this.tail = null;
    this.length = 0;
  }

  push(item) {
    const node = new Node(item)
    if (this.head == null) {
      this.head = node;
    } else {
      this.tail.next = node;
    }

    this.tail = node;
    this.length += 1;
  }

  pop() {
    const popItem = this.head;
    this.head = this.head.next;
    this.length -= 1;
    return popItem.item;
  }
}
const fs = require('fs');
const [S, K] = fs.readFileSync("./dev/stdin").toString().trim().split(" ").map(Number);


function solve(sb, bro) {
  if (sb == bro) {
    return 0;
  }
  let visited = Array.from(Array(2), () => Array(500001).fill(-1))
  let cnt = 1;
  let q = new Queue();
  q.push(sb);
  visited[0][sb] = 0;
  while (q.length > 0) {


    bro += cnt;


    const L = q.length;
    for (let i = 0; i < L; i++) {
      const now = q.pop();

      const next = [now + 1, now - 1, now * 2]
      for (let i = 0; i < 3; i++) {
        if (next[i] >= 0 && next[i] <= 500000 && visited[cnt % 2][next[i]] == -1) {
          visited[cnt % 2][next[i]] = cnt;
          if (next[i] == bro) {
            return cnt;
          }
          q.push(next[i]);
        }
      }
    }
    if (bro > 500000) {
      break;
    }
    if (visited[cnt % 2][bro] != -1) {
      return cnt;
    }
    cnt++;
  }

  return -1;
}


const answer = solve(S, K);
console.log(answer)