// -*- c++ -*-

 #include <iostream>

 #include <fstream>

 #include <list_graph.h>

 #include <smart_graph.h>

 #include <dimacs.h>

 #include <time_measure.h>

 #include <for_each_macros.h>

 #include <bfs_iterator.h>

 using namespace hugo;

 int main() {

   typedef ListGraph Graph; 

   typedef Graph::Node Node;

   typedef Graph::NodeIt NodeIt;

   typedef Graph::Edge Edge;

   typedef Graph::EdgeIt EdgeIt;

   typedef Graph::OutEdgeIt OutEdgeIt;

   Graph G;

   Node s, t;

   Graph::EdgeMap<int> cap(G);

   readDimacsMaxFlow(std::cin, G, s, t, cap);

   Graph::NodeMap<OutEdgeIt> pred(G);

   Timer ts;

   {

     ts.reset();

     Graph::NodeMap<bool> reached(G);

     /*Reverse_bfs from t, to find the starting level.*/

     reached.set(s, true);

     pred.set(s, INVALID);

     std::queue<Node> bfs_queue;

     bfs_queue.push(t);

     while (!bfs_queue.empty()) {

       Node v=bfs_queue.front();	

       bfs_queue.pop();

       OutEdgeIt e;

       for(G.first(e,v); G.valid(e); G.next(e)) {

 	Node w=G.head(e);

 	if (!reached[w]) {

 	  bfs_queue.push(w);

 	  reached.set(w, true);

 	  pred.set(w, e);

 	}

       }

     }

     std::cout << ts << std::endl;

   }

   {

     ts.reset();      

     BfsIterator5< Graph, Graph::NodeMap<bool> > bfs(G);

     bfs.pushAndSetReached(s);

     pred.set(s, INVALID);

     while (!bfs.finished()) { 

       ++bfs; 

       if (G.valid(bfs) && bfs.isBNodeNewlyReached()) 

 	pred.set(bfs.bNode(), bfs);

     }

     std::cout << ts << std::endl;

   }

   return 0;

 }