//Tests dijsktra.h with two heap implementations:
//the default binary heap of bin_heap.h, and the 
//Fibonacci heap of fib_heap.h.

//The input is a graph in standard dimacs format from the standard input (like
//in /hugo_loc/testfiles/dimacs). It runs dijkstra.h on this graph with both
//heaps, checking two postconditions:

//- if the edges e=uv of the shortest path tree reported by dijkstra.h have
//dist(v)-dist(u)=length(e)

// - if all edges e=uv with u reachable from the root have
//dist(v)-dist(u)>=length(e)
#include <iostream>
#include <math.h>

#include <hugo/smart_graph.h>
#include <hugo/dimacs.h>
#include <hugo/dijkstra.h>
#include <hugo/time_measure.h>
#include <hugo/bin_heap.h>
#include <hugo/fib_heap.h>

using namespace hugo;

int main(int, char **) {
  
  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 cap(G);
  readDimacsMaxFlow(std::cin, G, s, t, cap);
  Timer ts;
    
  std::cout <<
    "\n  Testing dijkstra.h with binary heap implementation bin_heap.h,"
	    <<std::endl;
  std::cout<<"  on a graph with " << 
    G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
	   << std::endl<<std::endl;
  
  Dijkstra<Graph, LengthMap> 
    dijkstra_test(G, cap);
  ts.reset();
  dijkstra_test.run(s);
  std::cout << "elapsed time: " << ts << std::endl;
  
  int error1=0;
  int error2=0;

  EdgeIt e;
  for(G.first(e); G.valid(e); G.next(e)) {
    Node u=G.tail(e);
    Node v=G.head(e);
    if ( dijkstra_test.dist(v) - dijkstra_test.dist(u) > cap[e] )
      if ( dijkstra_test.reached(u) ) {
	std::cout<<"Error! dist(head)-dist(tail)- edge_length= " 
		 <<dijkstra_test.dist(v) - dijkstra_test.dist(u) 
	  - cap[e]<<std::endl;
	++error1;
      }
  }

  NodeIt v;
  for(G.first(v); G.valid(v); G.next(v)) {
    if ( dijkstra_test.reached(v) ) {
      Edge e=dijkstra_test.pred(v);
      Node u=G.tail(e);
      if ( dijkstra_test.dist(v) - dijkstra_test.dist(u) != cap[e] ) {
	std::cout<<"Error in a shortest path tree edge! Difference: " 
		 <<std::abs(dijkstra_test.dist(v) - dijkstra_test.dist(u) 
			    - cap[e])<<std::endl;
	++error2;
      }
    }
  }


  
  std::cout << error1 << " non-tree and " << error2 
	    << " shortest path tree edge is erroneous."<<std::endl;



  std::cout <<
    "\n\n  Testing dijkstra.h with Fibonacci heap implementation fib_heap.h,"
	    <<std::endl;
  std::cout<<"  on a graph with " << 
    G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
	   << std::endl<<std::endl;
  
  Dijkstra<Graph, LengthMap, FibHeap> 
    dijkstra_test2(G, cap);
  ts.reset();
  dijkstra_test2.run(s);
  std::cout << "elapsed time: " << ts << std::endl;
  
  error1=0;
  error2=0;

  for(G.first(e); G.valid(e); G.next(e)) {
    Node u=G.tail(e);
    Node v=G.head(e);
    if ( dijkstra_test2.dist(v) - dijkstra_test2.dist(u) > cap[e] )
      if ( dijkstra_test2.reached(u) ) {
	std::cout<<"Error! dist(head)-dist(tail)- edge_length= " 
		 <<dijkstra_test2.dist(v) - dijkstra_test2.dist(u) 
	  - cap[e]<<std::endl;
	++error1;
      }
  }

  for(G.first(v); G.valid(v); G.next(v)) {
    if ( dijkstra_test2.reached(v) ) {
      Edge e=dijkstra_test2.pred(v);
      Node u=G.tail(e);
      if ( dijkstra_test2.dist(v) - dijkstra_test2.dist(u) != cap[e] ) {
	std::cout<<"Error in a shortest path tree edge! Difference: " 
		 <<std::abs(dijkstra_test2.dist(v) - dijkstra_test2.dist(u) 
			    - cap[e])<<std::endl;
	++error2;
      }
    }
  }


  std::cout << error1 << " non-tree and " << error2 
	    << " shortest path tree edge is erroneous."<<std::endl;


  return 0;
}