function gen(t) {
  let code = [0];
  function iter() {
    const origin = Array.from(code);
    code.reverse().forEach((v, i, code) => code[i] += code.length);
    code = origin.concat(code);
  }

  for (let i = 0; i < t; i++) iter();
  return code;
}

const gray = gen(5);
const string = "암호".toUpperCase();
const code = Array.from(string).map((c) => gray[c.charCodeAt(0) - 65]);

console.log(code);

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