This page runs on my old Redmi Note3 cellphone that only has very limited resources, programs with big memory or heavy cpu load do not allow to run here. If logs like 'std::bad_alloc' or 'Process exec time out' show on the console, that means your code consumes too much resouces. Currently, only 50MB heap memory can be used for single submition and the program must be finished in 20s. Enjoy yourself!