// -*- c++ -*-

 #ifndef HUGO_SUURBALLE_H

 #define HUGO_SUURBALLE_H

 #include <iostream>

 #include <dijkstra.h>

 #include <graph_wrapper.h>

 namespace hugo {

 ///\brief Implementation of Suurballe's algorithm

 ///

 /// The class \ref hugo::Suurballe "Suurballe" implements

 /// Suurballe's algorithm which seeks for k edge-disjoint paths

 /// from a given source node to a given target node in an

 /// edge-weighted directed graph having minimal total cost.

 /// 

 /// 

   template <typename Graph, typename T, 

     typename LengthMap=typename Graph::EdgeMap<T> >

   class Suurballe {

     //Writing maps 

     class ConstMap {

     public :

       typedef int ValueType;

       typedef typename Graph::Edge KeyType;

       int operator[](typename Graph::Edge e) const { 

 	return 1;

       } 

     };

     /*

     //    template <typename Graph, typename T>

     class ModLengthMap {   

       typedef typename Graph::EdgeMap<T> EdgeMap;

       typedef typename Graph::NodeMap<T> NodeMap;

       const EdgeMap &ol;   

       const NodeMap &pot;     

     public :

       typedef typename EdgeMap::KeyType KeyType;

       typedef typename EdgeMap::ValueType ValueType;

       double operator[](typename Graph::EdgeIt e) const {     

 	return 10;//ol.get(e)-pot.get(v)-pot.get(u);   

       }     

       ModLengthMap(const EdgeMap &o,

 		   const NodeMap &p) : 

 	ol(o), pot(p){}; 

     };

     */

     typedef typename Graph::Node Node;

     typedef typename Graph::NodeIt NodeIt;

     typedef typename Graph::Edge Edge;

     typedef typename Graph::OutEdgeIt OutEdgeIt;

     typedef TrivGraphWrapper<const Graph> TrivGraphType;

     typedef ResGraphWrapper<TrivGraphType,int,typename Graph::EdgeMap<int>,

       ConstMap> ResGraphType;

     const Graph& G;

     const LengthMap& length;

     //auxiliary variables

     typename Graph::EdgeMap<int> reversed; 

     typename Graph::NodeMap<T> dijkstra_dist; 

   public :

     Suurballe(Graph& _G, LengthMap& _length) : G(_G), 

       length(_length), reversed(_G), dijkstra_dist(_G){ }

     ///Runs Suurballe's algorithm

     ///Returns true iff there are k edge-disjoint paths from s to t

     bool run(Node s, Node t, int k) {

       LengthMap mod_length_c = length;

       ConstMap const1map;

       //ResGraphWrapper< Graph,T,typename Graph::EdgeMap<int>, ConstMap> 

       TrivGraphType ize(G);

       ResGraphType res_graph(ize, reversed, const1map);

       //ModLengthMap modified_length(length, dijkstra_dist);

       //Dijkstra<ResGraphType, ModLengthMap> dijkstra(res_graph, modified_length);

       //ResGraphWrapper< Graph,T,typename Graph::EdgeMap<int>, ConstMap>

       Dijkstra<ResGraphType, LengthMap> dijkstra(res_graph, mod_length_c);

       for (int i=0; i<k; ++i){

 	dijkstra.run(s);

 	if (!dijkstra.reached(t)){

 	  //There is no k path from s to t

 	  return false;

 	};

 	{

 	  //We have to copy the potential

 	  typename ResGraphType::EdgeIt e;

 	  for ( res_graph.first(e) ; res_graph.valid(e) ; res_graph.next(e) ) {

 	    //dijkstra_dist[e] = dijkstra.distMap()[e];

 	    mod_length_c[Edge(e)] = mod_length_c[Edge(e)] - 

 	      dijkstra.distMap()[res_graph.head(e)] +  

 	      dijkstra.distMap()[res_graph.tail(e)];

 	  }

 	}

 	//Reversing the sortest path

 	Node n=t;

 	Edge e;

 	while (n!=s){

 	  e = dijkstra.pred(n);

 	  n = dijkstra.predNode(n);

 	  reversed[e] = 1-reversed[e];

 	}

       }

       return true;

     }

   };//class Suurballe

 } //namespace hugo

 #endif //HUGO_SUURBALLE_H