Handwired is an OSS library that rewrites program if-statements and loops into a neural network that produces the same ...

Democrats and Republicans alike are coming out against data centre development, amid growing backlash across the US.

Much of the local news during October 1986 was centered on education, crime and sports making the mix. It was the beginning ...

A college event scheduling application that assigns events to suitable rooms and time slots while checking resource and availability constraints. Planning several college events at once can lead to ...

Finds the best combination of lab groups for your FRI timetable, with no overlaps. Every semester, students at the Faculty of Computer and Information Science (FRI, University of Ljubljana) get a ...

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如果是在浏览器里跑，那就只能用JavaScript引擎，这时候要注意避免写出可能导致 catastrophic backtracking 的模式。 注意：不管用哪个引擎，都要给正则匹配设置超时。 我见过太多因为一个正则跑了几分钟把整个服务拖垮的案例。 超时设置是最后一道防线，千万别省。

这就是典型的 灾难性回溯 （Catastrophic Backtracking）。 问题的根源在于嵌套量词： (a+)+ 会让正则引擎尝试所有可能的分组方式，当匹配失败时，回溯的次数呈指数级增长。 对于长度为n的字符串，最坏情况下需要尝试2的n次方种组合。 解决方案有两个层面。