Q:

How difficult are world cup bouldering problems?

Recently I watched a video summary of the boulder world cup in Munich.
Indoors and outdoors each boulder problem is classified with
a certain difficulty e.g. in the Hueco or in the Fontainbleau scale (https://en.wikipedia.org/wiki/Grade_%28bouldering%29) 
Which grades competitors have to face in the boulder world cup?

A:

Around FB 7c to 8a+.
I found an official source about the difficulty in world cup bouldering competitions. On the website of the world cup in Innsbruck they state that
Bouldering is also known as "max power discipline" and represents the probably most pretentious event of competition climbing. The difficulties of the boulder problems range between boulder grade 7c to 8a+.
(http://www.boulderworldcup-innsbruck.com/en/ergebnisse/wettkampfmodus.html)

