let res = stack.join('');
if (chunks === null) return null; // End of stream。业内人士推荐Line官方版本下载作为进阶阅读
Now, he's working on a two-legged version that will require even more responsive legs to keep its balance while lugging Bruton around.，推荐阅读im钱包官方下载获取更多信息
// 题目保证nums1的元素都在nums2中，无需额外判空