This is my entry for the Intel Threading Challenge, Phase 2, Problem 2, Amateur Level. Pre-requisites ============== - Threading Building Blocks (TBB). Tested with 3.0, may work(?) with earlier versions. - g++. Tested with 4.2.1 on OS X and 4.4.1 on Linux. Should work with other versions too. To build it =========== - Make sure the environment variables for 64-bit TBB are set up (e.g. by running the tbbvars.sh script that ships with TBB). - Run make That should be it. The executable it generates is called 'hailstone'. It compiles cleanly on the OS X (Snow Leopard, 64-bit) and Linux (Ubuntu 9.10, 64-bit) machines that I've tested. To run it ========= ./hailstone <lower> <upper> <max-length> <bucket-size> (as in the problem description). The output includes the time taken to calculate all the sequence lengths for the range (excluding printing them out at the end), using TBB's tick_count class.