[9] 回文数

/**
 * @param {number} x
 * @return {boolean}
 */
var isPalindrome = function (x) {
  if (x === 0) return true;
  if (x < 0 || x % 10 === 0) {
    return false;
  }
  let y = 0;
  while (x > y) {
    y = y * 10 + x % 10;
    x = (x - x % 10) / 10;
  }
  return x === y || x === (y - y % 10) / 10;
};