UnionFind
Changing the representation of the union-find
it has the same running time but it takes just 2/3 space
! does not auto insert items /performance/

UnionFindEnum
Changing the interface - more convenient to UnionFind
Does not based on the stl data structures /it could be disadvantage/
=> does not use singular iterator assignment /not stl conform, but always work/
Just new iterator interface

MaxMatching + UnionFindTest
Using new iterator interface instead of the old

 @nodeset

 label

 0

 1

 2

 3

 4

 5

 6

 @edgeset

         weight

 0   3   1

 0   4   1

 1   5   1

 5   2   1

 6   2   1

 0   1   1

 2   1   1

 3   4   1

 4   5   1

 5   6   1

 @end