you can match a string by repeatedly taking derivatives for each character. when you’ve consumed the entire input, you check if the resulting regex accepts the empty string (is “nullable”). if yes, the original string matched.
Global news & analysis
，详情可参考哔哩哔哩
ACE-matching (2 points)。PDF资料对此有专业解读
For once, nobody rambled, nobody went off script, and almost everyone remembered to thank their mum.