NO, this is not computer science. THIS is Europe. Each circle represents a country and each line represents a border. Position and size doesn't matter. It may seem hard, but the moment you understand, it will be easier.
EVERY border counts between European countries, even not in Europe
Countries without any land border have their maritime border in dotted lines
Vatican has a special thing and is the easiest to find
If one circle can correspond to multiple countries, use the sea.