progs/catastrophic/catastrophic.js
author Christian Urban <christian.urban@kcl.ac.uk>
Sun, 29 Oct 2023 13:05:09 +0000
changeset 948 6bb67c2dcfd3
parent 753 d94fdbef1a4f
permissions -rwxr-xr-x
updated

#!/usr/local/bin/node

// A case of catastrophic backtracking in JavaScript/Node.js
//
// regex: (a*)*b
// strings: aa...
//
// call with:
//
//  $> ./catastrophic.js 20
//
// call with timing as:
//
//  $> time ./catastrophic.js 25


const args = process.argv[2]

var str = 'a'.repeat(args);

console.log(str)

var re = /^((a)*)*b$/;

var res = re.test(str);

console.log(res)