diff -r d8475431bbbb -r 8e85e6bbefdf demo/sub_graph_adaptor_demo.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/sub_graph_adaptor_demo.cc	Mon May 23 04:48:14 2005 +0000
@@ -0,0 +1,80 @@
+// -*- c++ -*-
+
+// Use a DIMACS max flow file as stdin.
+// sub_graph_adaptor_demo < dimacs_max_flow_file
+// This program computes a maximum number of edge-disjoint shortest paths
+// between s and t.
+
+#include <iostream>
+#include <fstream>
+
+#include <lemon/smart_graph.h>
+#include <lemon/dijkstra.h>
+#include <lemon/maps.h>
+#include <lemon/graph_adaptor.h>
+#include <lemon/dimacs.h>
+#include <lemon/preflow.h>
+#include <tight_edge_filter_map.h>
+
+using namespace lemon;
+
+using std::cout;
+using std::endl;
+
+int main()
+{    
+  typedef SmartGraph Graph;
+
+  typedef Graph::Edge Edge;
+  typedef Graph::Node Node;
+  typedef Graph::EdgeIt EdgeIt;
+  typedef Graph::NodeIt NodeIt;
+  typedef Graph::EdgeMap<int> LengthMap;
+
+  Graph g;
+  Node s, t;
+  LengthMap length(g);
+
+  readDimacs(std::cin, g, length, s, t);
+
+  cout << "edges with lengths (of form id, source--length->target): " << endl;
+  for(EdgeIt e(g); e!=INVALID; ++e) 
+    cout << " " << g.id(e) << ", " << g.id(g.source(e)) << "--" 
+	 << length[e] << "->" << g.id(g.target(e)) << endl;
+
+  cout << "s: " << g.id(s) << " t: " << g.id(t) << endl;
+
+  typedef Dijkstra<Graph, LengthMap> Dijkstra;
+  Dijkstra dijkstra(g, length);
+  dijkstra.run(s);
+
+  // This map returns true exactly for those edges which are 
+  // tight w.r.t the length funcion and the potential 
+  // given by the dijkstra algorithm.
+  typedef TightEdgeFilterMap<Graph, const Dijkstra::DistMap, LengthMap> 
+    TightEdgeFilter;
+  TightEdgeFilter tight_edge_filter(g, dijkstra.distMap(), length);
+
+//  ConstMap<Node, bool> const_true_map(true);
+  // This graph contains exaclty the tight edges.
+// typedef SubGraphAdaptor<Graph, ConstMap<Node, bool>, TightEdgeFilter> SubGW;
+  typedef EdgeSubGraphAdaptor<Graph, TightEdgeFilter> SubGW;
+  SubGW gw(g, tight_edge_filter);
+
+  ConstMap<Edge, int> const_1_map(1);
+  Graph::EdgeMap<int> flow(g, 0);
+  // Max flow between s and t in the graph of tight edges.
+  Preflow<SubGW, int, ConstMap<Edge, int>, Graph::EdgeMap<int> > 
+    preflow(gw, s, t, const_1_map, flow);
+  preflow.run();
+
+  cout << "maximum number of edge-disjoint shortest path: " 
+       << preflow.flowValue() << endl;
+  cout << "edges of the maximum number of edge-disjoint shortest s-t paths: " 
+       << endl;
+  for(EdgeIt e(g); e!=INVALID; ++e) 
+    if (flow[e])
+      cout << " " << g.id(e) << ", "
+	   << g.id(g.source(e)) << "--" 
+	   << length[e] << "->" << g.id(g.target(e)) << endl;
+}