# HG changeset patch
# User marci
# Date 1075474144 0
# Node ID 8ff5dc7d18eb29239daece5fbd072f4d3b286143
# Parent  3ee2187d6342231d41d9d9e655d0f8d93f8daa87
marci_max_flow.hh in the new concept

diff -r 3ee2187d6342 -r 8ff5dc7d18eb src/work/edmonds_karp.hh
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/work/edmonds_karp.hh	Fri Jan 30 14:49:04 2004 +0000
@@ -0,0 +1,206 @@
+#ifndef MARCI_MAX_FLOW_HH
+#define MARCI_MAX_FLOW_HH
+
+#include <algorithm>
+
+#include <bfs_iterator.hh>
+
+namespace marci {
+
+  template<typename Graph, typename T>
+  class ResGraph {
+    typedef typename Graph::NodeIt NodeIt;
+    typedef typename Graph::EachNodeIt EachNodeIt;
+    typedef typename Graph::SymEdgeIt OldSymEdgeIt;
+    const Graph& G;
+    typename Graph::EdgeMap<T>& flow;
+    const typename Graph::EdgeMap<T>& capacity;
+  public:
+    ResGraph(const Graph& _G, typename Graph::EdgeMap<T>& _flow, 
+	     const typename Graph::EdgeMap<T>& _capacity) : 
+      G(_G), flow(_flow), capacity(_capacity) { }
+
+    class EdgeIt; 
+    class OutEdgeIt; 
+    friend class EdgeIt; 
+    friend class OutEdgeIt; 
+
+    class EdgeIt {
+      friend class ResGraph<Graph, T>;
+    protected:
+      const ResGraph<Graph, T>* resG;
+      OldSymEdgeIt sym;
+    public:
+      EdgeIt() { } 
+      //EdgeIt(const EdgeIt& e) : resG(e.resG), sym(e.sym) { }
+      T free() const { 
+	if (resG->G.aNode(sym)==resG->G.tail(sym)) { 
+	  return (resG->capacity.get(sym)-resG->flow.get(sym)); 
+	} else { 
+	  return (resG->flow.get(sym)); 
+	}
+      }
+      bool valid() const { return sym.valid(); }
+      void augment(const T a) const {
+	if (resG->G.aNode(sym)==resG->G.tail(sym)) { 
+	  resG->flow.set(sym, resG->flow.get(sym)+a);
+	} else { 
+	  resG->flow.set(sym, resG->flow.get(sym)-a);
+	}
+      }
+    };
+
+    class OutEdgeIt : public EdgeIt {
+      friend class ResGraph<Graph, T>;
+    public:
+      OutEdgeIt() { }
+      //OutEdgeIt(const OutEdgeIt& e) { resG=e.resG; sym=e.sym; }
+    private:
+      OutEdgeIt(const ResGraph<Graph, T>& _resG, const NodeIt v) { 
+      	resG=&_resG;
+	sym=resG->G.template first<OldSymEdgeIt>(v);
+	while( sym.valid() && !(free()>0) ) { ++sym; }
+      }
+    public:
+      OutEdgeIt& operator++() { 
+	++sym; 
+	while( sym.valid() && !(free()>0) ) { ++sym; }
+	return *this; 
+      }
+    };
+
+    void getFirst(OutEdgeIt& e, const NodeIt v) const { 
+      e=OutEdgeIt(*this, v); 
+    }
+    void getFirst(EachNodeIt& v) const { G.getFirst(v); }
+    
+    template< typename It >
+    It first() const { 
+      It e;
+      getFirst(e);
+      return e; 
+    }
+
+    template< typename It >
+    It first(const NodeIt v) const { 
+      It e;
+      getFirst(e, v);
+      return e; 
+    }
+
+    NodeIt tail(const EdgeIt e) const { return G.aNode(e.sym); }
+    NodeIt head(const EdgeIt e) const { return G.bNode(e.sym); }
+
+    NodeIt aNode(const OutEdgeIt e) const { return G.aNode(e.sym); }
+    NodeIt bNode(const OutEdgeIt e) const { return G.bNode(e.sym); }
+
+    int id(const NodeIt v) const { return G.id(v); }
+
+    template <typename ValueType>
+    class NodeMap {
+      //const ResGraph<Graph, T>& G; 
+      typename Graph::NodeMap<ValueType> node_map; 
+    public:
+      NodeMap(const ResGraph<Graph, T>& _G) : node_map(_G.G)/*: G(_G)*/ { }
+      NodeMap(const ResGraph<Graph, T>& _G, const ValueType a) : node_map(_G.G, a) /*: G(_G)*/ { }
+      void set(const NodeIt nit, const ValueType a) { node_map.set(nit, a); }
+      ValueType get(const NodeIt nit) const { return node_map.get(nit); }
+    };
+
+  };
+
+  template <typename Graph, typename T>
+  struct max_flow_type {
+    typedef typename Graph::NodeIt NodeIt;
+    typedef typename Graph::EdgeIt EdgeIt;
+    typedef typename Graph::EachEdgeIt EachEdgeIt;
+    typedef typename Graph::OutEdgeIt OutEdgeIt;
+    typedef typename Graph::InEdgeIt InEdgeIt;
+    const Graph& G;
+    NodeIt s;
+    NodeIt t;
+    typename Graph::EdgeMap<T> flow;
+    const typename Graph::EdgeMap<T>& capacity;
+
+    max_flow_type(const Graph& _G, NodeIt _s, NodeIt _t, const typename Graph::EdgeMap<T>& _capacity) : G(_G), s(_s), t(_t), flow(_G, 0), capacity(_capacity) { }
+    void run() {
+      typedef ResGraph<Graph, T> AugGraph;
+      AugGraph res_graph(G, flow, capacity);
+
+      bool augment;
+      do {
+	augment=false;
+
+	typedef typename AugGraph::OutEdgeIt AugOutEdgeIt;
+	typedef typename AugGraph::EdgeIt AugEdgeIt;
+	typedef std::queue<AugOutEdgeIt> BfsQueue;
+	BfsQueue bfs_queue;
+	bfs_queue.push(res_graph.template first<AugOutEdgeIt>(s));
+
+	typedef typename AugGraph::NodeMap<bool> ReachedMap;
+	ReachedMap reached(res_graph, false);
+	reached.set(s, true); 
+	
+	bfs_iterator1< AugGraph, ReachedMap > 
+	res_bfs(res_graph, bfs_queue, reached);
+
+	typedef typename AugGraph::NodeMap<AugEdgeIt> PredMap;
+	PredMap pred(res_graph);
+	//typename AugGraph::EdgeIt a; //invalid
+	//a.makeInvalid();
+	//pred.set(s, a);
+
+	typedef typename AugGraph::NodeMap<int> FreeMap;
+	FreeMap free(res_graph);
+	
+	//searching for augmenting path
+	while ( res_bfs.valid() ) { 
+	  //std::cout<<"KULSO ciklus itt jar: "<<G.id(res_graph.tail(res_bfs))<<"->"<<G.id(res_graph.head(res_bfs))<<std::endl;
+	  if (res_bfs.newly_reached()) {
+	    AugOutEdgeIt e=AugOutEdgeIt(res_bfs);
+	    NodeIt v=res_graph.tail(e);
+	    NodeIt w=res_graph.head(e);
+	    //std::cout<<G.id(v)<<"->"<<G.id(w)<<", "<<G.id(w)<<" is newly reached";
+	    pred.set(w, e);
+	    if (pred.get(v).valid()) {
+	      free.set(w, std::min(free.get(v), e.free()));
+	      //std::cout <<" nem elso csucs: ";
+	      //std::cout <<"szabad kap eddig: "<< free.get(w) << " ";
+	    } else {
+	      free.set(w, e.free()); 
+	      //std::cout <<" elso csucs: ";
+	      //std::cout <<"szabad kap eddig: "<< free.get(w) << " ";
+	    }
+	    //std::cout<<std::endl;
+	  }
+	
+	  if (res_graph.head(res_bfs)==t) break;
+	  ++res_bfs;
+	} //end searching augmenting path
+	if (reached.get(t)) {
+	  augment=true;
+	  NodeIt n=t;
+	  T augment_value=free.get(t);
+	  std::cout<<"augmentation: ";
+	  while (pred.get(n).valid()) { 
+	    AugEdgeIt e=pred.get(n);
+	    e.augment(augment_value); 
+	    std::cout<<"("<<res_graph.tail(e)<< "->"<<res_graph.head(e)<<") ";
+	    n=res_graph.tail(e);
+	  }
+	  std::cout<<std::endl;
+	}
+
+	std::cout << "actual flow: "<< std::endl;
+	for(EachEdgeIt e=G.template first<EachEdgeIt>(); e.valid(); ++e) { 
+	  std::cout<<"("<<G.tail(e)<< "-"<<flow.get(e)<<"->"<<G.head(e)<<") ";
+	}
+	std::cout<<std::endl;
+
+      } while (augment);
+    }
+  };
+
+} // namespace marci
+
+#endif //MARCI_MAX_FLOW_HH