Hi! Recently I've found interesting ACM research on C++ and Java efficiency. This task also was been solved on lisp/scheme and is described on http://www.flownet.com/ron/papers/lisp-java/ I tried to solve this task on Haskell but stuck with efficiency problems (approx in 1000 times slower and takes 20 times more memory). I hope the approach, I've used is correct and problem with data structures and implementation. It took more than 81% of time for garbage collection. I tried to use ByteStrings instead of Strings, but unfortunately it didn't help. The entire code I placed on http://hpaste.org/fastcgi/hpaste.fcgi/view?id=2764 The original instructions are on: http://www.flownet.com/ron/papers/lisp-java/instructions.html Dictionary file could be downloaded from: http://www.flownet.com/ron/papers/lisp-java/dictionary. Input data: http://www.flownet.com/ron/papers/lisp-java/input.txt Expected output: http://www.flownet.com/ron/papers/lisp-java/output.txt Could someone help me to make this code faster? I'd like to see solution that will be elegant and fast, without heavy optimizations, that will make code unreadable. Also, if it possible, prepare the program to support SMP parallelism. Very thanks in advance. Hope you'll enjoy this task :) -- Best regards, Vasyl Pasternak