src/work/marci/bfsit_vs_byhand.cc
author jacint
Wed, 29 Sep 2004 14:12:26 +0000
changeset 920 2d6c8075d9d0
parent 773 ce9438c5a82d
child 921 818510fa3d99
permissions -rw-r--r--
some changes in the doc to make things clearer
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// -*- c++ -*-
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#include <iostream>
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#include <fstream>
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#include <sage_graph.h>
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#include <hugo/smart_graph.h>
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#include <hugo/dimacs.h>
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#include <hugo/time_measure.h>
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//#include <hugo/for_each_macros.h>
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#include <bfs_dfs.h>
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using namespace hugo;
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using std::cout;
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using std::endl;
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int main() {
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  typedef SageGraph Graph; 
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  typedef Graph::Node Node;
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  typedef Graph::NodeIt NodeIt;
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  typedef Graph::Edge Edge;
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  typedef Graph::EdgeIt EdgeIt;
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  typedef Graph::OutEdgeIt OutEdgeIt;
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  Graph g;
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  //Node s;
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  //Graph::EdgeMap<int> cap(g);
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  //readDimacsMaxFlow(std::cin, g, s, t, cap);
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  readDimacs(std::cin, g);
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  NodeIt s;
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  g.first(s);
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  cout << g.nodeNum() << endl;
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  cout << g.edgeNum() << endl;
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  Graph::NodeMap<Edge> pred(g);
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  cout << "iteration time of bfs written by hand..." << endl;
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  Timer ts;
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  {
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    ts.reset();
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    Graph::NodeMap<bool> reached(g);
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    reached.set(s, true);
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    pred.set(s, INVALID);
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    std::queue<Node> bfs_queue;
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    bfs_queue.push(s);
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    while (!bfs_queue.empty()) {
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      Node v=bfs_queue.front();	
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      bfs_queue.pop();
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      OutEdgeIt e;
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      for(g.first(e,v); g.valid(e); g.next(e)) {
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	Node w=g.head(e);
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	if (!reached[w]) {
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	  bfs_queue.push(w);
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	  reached.set(w, true);
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	  pred.set(w, e);
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	}
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      }
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    }
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    std::cout << ts << std::endl;
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  }
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  cout << "iteration time with bfs iterator..." << endl;
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  {
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    ts.reset();      
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    BfsIterator< Graph, Graph::NodeMap<bool> > bfs(g);
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    bfs.pushAndSetReached(s);
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    pred.set(s, INVALID);
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    while (!bfs.finished()) { 
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      ++bfs; 
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      if (g.valid(bfs) && bfs.isBNodeNewlyReached()) 
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	pred.set(bfs.head(), Graph::Edge(bfs));
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    }
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    std::cout << ts << std::endl;
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  }
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  return 0;
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}