Branchy version

[artsiomkorzun]

Check List:

• [ x] Tests pass (./test.sh <username> shows no differences between expected and actual outputs)
• [x ] All formatting changes by the build are committed
• [x ] Your launch script is named calculate_average_<username>.sh (make sure to match casing of your GH user name) and is executable
• [x ] Output matches that of calculate_average_baseline.sh

• Execution time: a bit better
• Execution time of reference implementation: a lot