According to MIT computer scientists, Super Mario Bros is harder than NP. An NP problem is a problem whose complexity does not increase polynomially, but instead rises exponentially as more values need to be concerned. An example of an NP problem is finding a complete factorisation of a 1,000 digit long number. However, if you have a suggested list of primes then it takes seconds to verify whether this list is the list. Apparently, Super Mario Bros. is harder than any of this and it would take an exponential amount of time to verify any solution of the game just by computer simulations.