<li> If you want to design a network and want to minimize the total length

 <li> If you want to design a network and want to minimize the total

 of wires then you might be looking for a <b>minimum spanning tree</b> in

 length of wires then you might be looking for a <b>minimum spanning

 an undirected graph. This can be found using the Kruskal algorithm: the 

 tree</b> in an undirected graph. This can be found using the Kruskal

 function \ref lemon::kruskal "LEMON Kruskal ..." does this job for you.

 algorithm: the function \ref lemon::kruskal "LEMON Kruskal " does

 The following code fragment shows an example:

 this job for you.  After we had a graph \c g and a cost map \c

 edge_cost_map , the following code fragment shows an example how to get weight of the minmum spanning tree, if the costs are uniform:

 Ide Zsuzska fog irni!

 \dontinclude kruskal_demo.cc

 \skip std::cout 

 \until kruskal

 It gives back a edge bool map, which contains the edges of the tree.

 If the costs are non-uniform, for example  the cost is given by \c

 edge_cost_map_2 , or the edges of the tree are have to be given in a

 vector, then we can give to the kruskal a vector \c tree_edge_vec , instead of

 an edge bool map:

 \skip edge_cost_map_2 

 \until edge_cost_map_2, std::back_inserter

 And finally the next fragment shows how to use the functions \c makeKruskalMapInput and \c makeKruskalSequenceOutPut:

 \skip makeKruskalSequenceOutput

 \until tree_edge_vec

 See the whole program in \ref kruskal_demo.cc.