1
/**
2
 * @param {number} target
3
 * @return {number}
4
 */
5
var racecar = function (target) {
6
  const queue = [{ position: 0, speed: 1, sequence: "" }];
7

8
  while (queue.length) {
9
    let { position, speed, sequence } = queue.shift();
10

11
    if (position === target) return sequence.length;
12

13
    const newPosition = position + speed;
14

15
    queue.push({
16
      position: newPosition,
17
      speed: speed * 2,
18
      sequence: sequence + "A",
19
    });
20

21
    if (
22
      (newPosition > target && speed > 0) ||
23
      (newPosition < target && speed < 0)
24
    ) {
25
      queue.push({
26
        sequence: sequence + "R",
27
        position,
28
        speed: Math.sign(speed) === 1 ? -1 : 1,
29
      });
30
    }
31
  }
32

33
  return 0;
34
};