progs/catastrophic.py
author Christian Urban <urbanc@in.tum.de>
Sun, 27 Oct 2019 13:55:43 +0000
changeset 676 62d168bf7ac8
parent 613 bfd511b7ecbf
child 701 681c36b2af27
permissions -rwxr-xr-x
ypdated

#!/usr/bin/env python
import re
import sys

# case of catastrophic backtracking in Python
#
# regex: (a*)*b
# strings: aa...a
#
# call with timing as:
#
#   > time ./catastrophic.py 20

# counter n given on the command line
cn = sys.argv[1]

# calling the matching function
s = ("a" * int(cn))
m = re.match('(a*)*b' , s) 

print s