简单题 ,但是没做这一题, 没看懂题的意思…

const alphabetBoardPath = function (target) {
  let xi, yi, res = '', lx = 0, ly = 0;
  for (const c of target) {
    xi = (c.charCodeAt() - 97) % 5;
    yi = parseInt((c.charCodeAt() - 97) / 5);
    res += 'U'.repeat(Math.max(0, ly - yi));
    res += 'R'.repeat(Math.max(0, xi - lx));
    res += 'L'.repeat(Math.max(0, lx - xi));
    res += 'D'.repeat(Math.max(0, yi - ly));
    res += '!';
    lx = xi;
    ly = yi;
  }
  return res;
};