bronto,
I am not sure why eliminating too many repeated characters is a requirement, but here is a
node that was a contest to find the most efficient way to get the number of unique characters in a string. From a brute force perspective - it is no easier to crack the password abcde then it is ppppp.
As far as identifying repeating sequence of characters, I do not know of an efficient method to do this, but:
Use substr with various lengths and starting positions
Use my $count = $temp_pass =~ s/$substring//g
To get the count of how often the sequence repeats in the password. Again, I do not understand the point of this.
I hope this helps - L~R