const { readInput } = require("./util");

const { lines } = readInput();

function binToInt(binString, oneChar = "1") {
  const binArr = Array.from(binString).reverse();
  let num = 0;
  for (let i = 0; i < binArr.length; i++) {
    if (binArr[i] === oneChar) {
      num += 2 ** i;
    }
  }
  return num;
}

function seatId(pass) {
  const row = binToInt(pass.slice(0, 7), "B");
  const col = binToInt(pass.slice(7, 11), "R");
  return row * 8 + col;
}

const seatIds = new Set(lines.map(seatId));

const maxSeatId = seatId("BBBBBBBRRR");
console.log(maxSeatId);

for (let i = 0; i <= maxSeatId; i++) {
  if (!seatIds.has(i) && seatIds.has(i - 1) && seatIds.has(i + 1)) {
    console.log(i);
  }
}