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#include "Graph/Path.h"
#include "Graph/BidirectionalBFS.h"
#include "Graph/BidirectionalBFSVisitor.h"
#include "Common/UnorderedMap.h"
#include <boost/graph/adjacency_list.hpp>
#include <gtest/gtest.h>
using namespace std;
static const bool DEBUG = false;
typedef boost::adjacency_list<boost::vecS, boost::vecS,
boost::bidirectionalS> Graph;
// note: vertex_descriptor for adjacency_list<> is int
typedef boost::graph_traits<Graph>::vertex_descriptor Vertex;
// note: edge_descriptor for adjacency_list<> is int
typedef boost::graph_traits<Graph>::edge_descriptor Edge;
class TestVisitor : public BidirectionalBFSVisitor<Graph>
{
public:
typedef unordered_map<Vertex, Direction> DirMap;
typedef unordered_map<Vertex, int> RankMap;
typedef vector<Edge> EdgeList;
DirMap dirMap;
RankMap rankMap;
EdgeList commonEdges;
int rank;
TestVisitor() : rank(0) { }
BFSVisitorResult discover_vertex(const Vertex& u, const Graph&, Direction dir,
unsigned)
{
if (DEBUG)
cerr << dir << ": discover_vertex " << u << "\n";
return SUCCESS;
}
void examine_vertex(const Vertex& u, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": examine_vertex " << u << "\n";
dirMap[u] = dir;
rankMap[u] = rank++;
}
void examine_edge(const Edge& e, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": examine_edge " << e << "\n";
}
BFSVisitorResult tree_edge(const Edge& e, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": tree_edge " << e << "\n";
return SUCCESS;
}
BFSVisitorResult common_edge(const Edge& e, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": common_edge " << e << "\n";
commonEdges.push_back(e);
return SUCCESS;
}
BFSVisitorResult non_tree_edge(const Edge& e, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": non_tree_edge " << e << "\n";
commonEdges.push_back(e);
return SUCCESS;
}
void gray_target(const Edge& e, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": gray_target " << e << "\n";
}
void black_target(const Edge& e, const Graph&, Direction dir)
{
if (DEBUG)
cerr << dir << ": black_target " << e << "\n";
}
};
namespace {
class BidirectionalBFSTest : public ::testing::Test {
protected:
Graph linearGraph;
Graph branchingGraph;
BidirectionalBFSTest() {
add_edge(0, 1, linearGraph);
add_edge(1, 2, linearGraph);
add_edge(2, 3, linearGraph);
add_edge(0, 1, branchingGraph);
add_edge(0, 2, branchingGraph);
add_edge(1, 3, branchingGraph);
add_edge(3, 4, branchingGraph);
add_edge(4, 6, branchingGraph);
add_edge(5, 6, branchingGraph);
}
};
TEST_F(BidirectionalBFSTest, AlternatesDirection)
{
TestVisitor visitor;
bidirectionalBFS(linearGraph, 0, 3, visitor);
TestVisitor::DirMap& dir = visitor.dirMap;
ASSERT_EQ(dir[0], FORWARD);
ASSERT_EQ(dir[3], REVERSE);
ASSERT_EQ(dir[1], FORWARD);
ASSERT_EQ(dir[2], REVERSE);
}
TEST_F(BidirectionalBFSTest, FollowsBreadthFirstOrder)
{
TestVisitor visitor;
bidirectionalBFS(branchingGraph, 0, 6, visitor);
TestVisitor::RankMap& rank = visitor.rankMap;
ASSERT_TRUE(rank[1] > rank[0]);
ASSERT_TRUE(rank[2] > rank[0]);
ASSERT_TRUE(rank[3] > rank[1]);
ASSERT_TRUE(rank[3] > rank[2]);
ASSERT_TRUE(rank[3] > rank[4]);
ASSERT_TRUE(rank[3] > rank[5]);
ASSERT_TRUE(rank[4] > rank[6]);
ASSERT_TRUE(rank[5] > rank[6]);
}
TEST_F(BidirectionalBFSTest, IdentifiesCommonEdge)
{
TestVisitor visitor;
bidirectionalBFS(linearGraph, 0, 3, visitor);
TestVisitor::EdgeList& commonEdges = visitor.commonEdges;
// Note: Each common edge is visited twice. It is
// visited once by the forward traversal and once
// by the reverse traversal.
ASSERT_TRUE(commonEdges.size() == 2);
ASSERT_TRUE(commonEdges[0] == commonEdges[1]);
ASSERT_TRUE(source(commonEdges[0], linearGraph) == 1u);
ASSERT_TRUE(target(commonEdges[0], linearGraph) == 2u);
}
}
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