Hello all, Now I have an IO-problem, too. SPOJ problem 41 asks basically to determine whether a directed graph allows a path that uses every edge exactly once. The data from which the graphs are to be constructed are contained in a (huge) file, every item (number of test cases, size of test case, edges) on a single line. I've created my own test case file (much smaller, but already 217 MB, 2.2 million lines) to check my programme's performance. Now profiling reveals that over 90% of time and allocation are consumed by reading the file (line by line, reading the whole file as a lazy String and then chopping that to pieces is rather worse). So how do I quickly 1. read an Integer n from the file, 2. read the next n lines and 3. pass the first and last letter of those to the function that builds and checks the graph? When that is achieved, I could see whether my algorithm is good. Thanks for any help, Daniel -- "In My Egotistical Opinion, most people's C programs should be indented six feet downward and covered with dirt." -- Blair P. Houghton