removeMultiArcs function go through the arcs
list of a given graph and check if there are more than one
arc between two nodes. If exist more than one, the function
keeps one with minimum cost and remove the others.
matrix with the list of arcs of the graph. Each row represents one arc. The first two columns contain the two endpoints of each arc and the third column contains their weights.
logical value indicating whether the
graph is directed (
removeMultiArcs returns a new list of arcs without
any of the multi-arcs founded.