const fs = require("fs");

const input = fs.readFileSync("input", "utf-8").trim().split("\n");

function main() {
  // original mask string
  let mask = null;
  const memory = [];
  for (const line of input) {
    if (line.startsWith("mask")) {
      mask = line.slice(7);
    } else {
      const address = parseInt(line.slice(4));
      const num = BigInt(parseInt(line.split(" = ")[1]));
      memory[address] = apply(num, mask);
      // debug(num, mask);
    }
  }
  const sum = memory.reduce((a, b) => a + b, 0n);
  console.log("Solution:");
  console.log(sum.toString());
}

function debug(value, mask) {
  const result = apply(value, mask);
  console.log("=".repeat(18), " DEBUG ", "=".repeat(18));
  console.log(`value:  ${numToBin(value)}  (decimal ${value})`);
  console.log(`mask:   ${mask}`);
  console.log(`result: ${numToBin(result)}  (decimal ${result})`);
}

function numToBin(num) {
  return num.toString(2).padStart(36, "0");
}

function binToNum(bin) {
  return BigInt(parseInt(bin, 2));
}

function apply(num, mask) {
  num = num & binToNum(mask.replaceAll("X", 1));
  num = num | binToNum(mask.replaceAll("X", 0));
  return num;
}

main();