/**
* Determines a depth-first order for the edge-weighted digraph <tt>G</tt>.
*
* @param G the edge-weighted digraph
*/
public DepthFirstOrder(MapGraph G) {
pre = new int[G.V()];
post = new int[G.V()];
postorder = new Queue<Integer>();
preorder = new Queue<Integer>();
marked = new boolean[G.V()];
for (int v = 0; v < G.V(); v++) if (!marked[v]) dfs(G, v);
}
