At the Royal Institute of Technology (KTH), Stockholm a tool was developed called KATTIS (https://kth.kattis.com/ https://kth.kattis.com/) that not only check s

At the Royal Institute of Technology (KTH), Stockholm a tool was developed called KATTIS (https://kth.kattis.com/ https://kth.kattis.com/) that not only check submitted code for plagiarism but also verifies it with test input/output as well as measuring execution time/memory usage. There is a paper with more details "Five Years with Kattis - Using an Automated Assessment System in Teaching", https://www.csc.kth.se/~gkreitz/kattis-fie11/ https://www.csc.kth.se/~gkreitz/kattis-fie11/ The system is still developed and there is now an open version of it with a huge problem archive (competitive programming style) used by several universities: https://open.kattis.com/ https://open.kattis.com/ Trivia: KATTIS was originally very much developed by KTH's successful competitive programming team "Three-headed monkey", consisting of some PhD students (https://www.csc.kth.se/~gkreitz/ https://www.csc.kth.se/~gkreitz/) that did their thesis on stuff like streaming and encryption which in turn resulted in the company... Spotify.