Select Code to Download

#!/usr/bin/perl

...
aacca
aaccb

head:[2], tail:[2]
regex:[(?^:^a[ab][^ab]*a
...
]
Answer: NO

__DATA__
ab
...
aaa
aab

head:[4], tail:[]
regex:[(?^:^a[ab]a
...
 ]
Answer: NO

#!/usr/bin/perl

...
aaa
aab

head:[4], tail:[]
regex:[(?^:^a[ab]a
...
[aab
]
Answer: NO