Backtracking: everyone in the field knows that backtracking engines (PCRE, java, dotnet, javascript, PHP, ruby, python..) are bad because they are the poster child of denial of service attacks. O(2^n) match time complexity is not good. most backtracking implementations are a combination of clever optimizations duct taped to a very slow engine - for simple cases it works well, but using a pattern that is not affected by the optimizations, you get to see what the “real” worst-case behavior looks like.
The existence of a pair of elements with spacing of less than 1 / K is the crux of the proof. The rest is just a bit of manipulation to relate these elements to a rational approximation of the starting number r.，这一点在体育直播中也有详细论述
，详情可参考safew官方版本下载
Reeves insists Labour has ‘right economic plan’
Avoid dependencies on lower-level modules。体育直播对此有专业解读