Note that the problems are categorized with languages most appropriate to be used with them.
You might solve them with any language of your choice and it's totally upto you but for your own sanity, you
should try using the appropriate language.
Some problems on DomeCode's Practice module exist such that they might be challenging for some users. Hence,
solving problems researching for appropriate help with a concept is an important set of skill. While you'll
to find the resources on DomeCode itself since with every release, the resources gathered increase both in
and quantity, it is important to try this by yourself.
While a lot of competitive programming happening on-site disbars the use of Internet, in the real world of development, it's almost impossible to get around without looking up documentations, forums and the internet in general.
DomeCode's goal isn't to teach you competitive programming, it's primary objective is to advance your coding skills and practice them along with being able to use the features that would make the experience simply better for you without having to leave a single workspace.