You can just sort edges in non-increasing order and add them sequentially until there are two or more connectivity components...

It is absolutely of no importance
How many edges are used
Only the size if the largest edge matters
I DON'T KNOW why the problem rating is not 80, but 300.

Don't say things like
There you need DSU
Anansi's Cobweb requires DSU
And it is only 170 rating points