src/demo/coloring.cc
changeset 1431 ad44b1dd8013
equal deleted inserted replaced
-1:000000000000 0:e4617908bbfa
       
     1 #include <vector>
       
     2 
       
     3 #include <lemon/smart_graph.h>
       
     4 #include <lemon/bin_heap.h>
       
     5 #include <lemon/graph_reader.h>
       
     6 #include <lemon/graph_to_eps.h>
       
     7 
       
     8 using namespace std;
       
     9 using namespace lemon;
       
    10 
       
    11 int main() {
       
    12   typedef UndirSmartGraph Graph;
       
    13   typedef Graph::Node Node;
       
    14   typedef Graph::NodeIt NodeIt;
       
    15   typedef Graph::UndirEdge UndirEdge;
       
    16   typedef Graph::IncEdgeIt IncEdgeIt;
       
    17 
       
    18   Graph graph;
       
    19 
       
    20   UndirGraphReader<Graph> reader(std::cin, graph);
       
    21   Graph::NodeMap<xy<double> > coords(graph);
       
    22   reader.readNodeMap("coords", coords);
       
    23   
       
    24   reader.run();
       
    25 
       
    26   Graph::NodeMap<int> color(graph, -2);
       
    27   
       
    28   Graph::NodeMap<int> heapMap(graph, -1);
       
    29   BinHeap<Node, int, Graph::NodeMap<int> > heap(heapMap);
       
    30   
       
    31   for (NodeIt it(graph); it != INVALID; ++it) {
       
    32     heap.push(it, countOutEdges(graph, it));
       
    33   }
       
    34 
       
    35   vector<Node> order;
       
    36 
       
    37   while (!heap.empty()) {
       
    38     Node node = heap.top();
       
    39     heap.pop();
       
    40     color[node] = -1;
       
    41     order.push_back(node);
       
    42     for (IncEdgeIt it(graph, node); it != INVALID; ++it) {
       
    43       Node target = graph.runningNode(it); 
       
    44       if (color[target] == -2) {
       
    45 	heap.decrease(target, heap[target] - 1);
       
    46       }
       
    47     }
       
    48   }
       
    49 
       
    50   for (int i = order.size() - 1; i >= 0; --i) {
       
    51     set<int> forbidden;
       
    52     for (IncEdgeIt it(graph, order[i]); it != INVALID; ++it) {
       
    53       Node target = graph.runningNode(it); 
       
    54       if (color[target] != -1) {
       
    55 	forbidden.insert(color[target]);
       
    56       }
       
    57     }
       
    58     int current = 0;
       
    59     while (forbidden.find(current) != forbidden.end()) ++current;
       
    60     color[order[i]] = current;
       
    61   }
       
    62 
       
    63   ColorSet colorSet;
       
    64 
       
    65   graphToEps(graph, "six_coloring.eps").
       
    66     title("Six Colored Graph").copyright("(C) 2005 LEMON Project").
       
    67     coords(coords).nodeColors(composeMap(colorSet, color)).
       
    68     scaleToA4().run();
       
    69 
       
    70   return 0;
       
    71 }