93.复原-ip-地址 ​

/**
 * @param {string} s
 * @return {string[]}
 */
var restoreIpAddresses = function (s) {
  const length = s.length;
  const res = [];
  function fn(s, path, len) {
    if (path.length > 4) {
      return;
    }
    if (len === length && path.length === 4) {
      res.push(path.join("."));
      return;
    }
    for (let i = 0; i < s.length; i++) {
      const cur = s.slice(0, i + 1);
      const next = s.slice(i + 1);
      if (cur.length > 3 || +cur > 255) break;
      if (cur.length > 1 && cur[0] === "0") break;
      fn(next, path.concat(cur), len + cur.length);
    }
  }
  fn(s, [], 0);
  return res;
};

/**
 * @param {string} s
 * @return {string[]}
 */
var restoreIpAddresses = function (s) {
  const length = s.length;
  const res = [];
  function fn(s, path, len) {
    if (path.length > 4) {
      return;
    }
    if (len === length && path.length === 4) {
      res.push(path.join("."));
      return;
    }
    for (let i = 0; i < s.length; i++) {
      const cur = s.slice(0, i + 1);
      const next = s.slice(i + 1);
      if (cur.length > 3 || +cur > 255) break;
      if (cur.length > 1 && cur[0] === "0") break;
      fn(next, path.concat(cur), len + cur.length);
    }
  }
  fn(s, [], 0);
  return res;
};