This is solution for problem rubyquiz #153.
It finds longest repeated substrings using Karp-Miller-Rosenberg algorithm with complexity O(n * logn * logn). On my notebook (Intel Core 2 Duo 2.16 GHz) calculating longest substring in Homer's 'Illiad' ('test/homer-illiad.in') takes about 3 minutes.
bin/kmr.rb (note: input comes from standard input)
bin/kmr.rb string
bin/kmr.rb -f filename