From 8ba19d2dd02c9b9b9751d886cf85b20ac5ba8666 Mon Sep 17 00:00:00 2001
From: David Rosca <roscadav@fit.cvut.cz>
Date: Sat, 7 Mar 2015 12:29:23 +0100
Subject: [PATCH] Graph algo: Add DFS + tests
---
alib2algo/src/graph/traverse/Dfs.cpp | 71 ++++++++
alib2algo/src/graph/traverse/Dfs.h | 34 ++++
alib2algo/test-src/graph/traverse/DfsTest.cpp | 158 ++++++++++++++++++
alib2algo/test-src/graph/traverse/DfsTest.h | 20 +++
4 files changed, 283 insertions(+)
create mode 100644 alib2algo/src/graph/traverse/Dfs.cpp
create mode 100644 alib2algo/src/graph/traverse/Dfs.h
create mode 100644 alib2algo/test-src/graph/traverse/DfsTest.cpp
create mode 100644 alib2algo/test-src/graph/traverse/DfsTest.h
diff --git a/alib2algo/src/graph/traverse/Dfs.cpp b/alib2algo/src/graph/traverse/Dfs.cpp
new file mode 100644
index 0000000000..30f00d3ce8
--- /dev/null
+++ b/alib2algo/src/graph/traverse/Dfs.cpp
@@ -0,0 +1,71 @@
+#include "Dfs.h"
+
+#include <stack>
+#include <unordered_map>
+
+namespace graph
+{
+
+namespace traverse
+{
+
+struct Data
+{
+ Node start;
+ std::function<bool(const Node&)> func;
+};
+
+template <typename T>
+static void dfs_impl(const T &graph, const Node &start, std::function<bool(const Node&)> func)
+{
+ std::unordered_map<Node, bool> visited;
+ std::stack<Node> s;
+
+ s.push(start);
+ while (!s.empty()) {
+ Node n = s.top(); s.pop();
+ if (visited.find(n) == visited.end()) {
+ if (!func(n)) {
+ return;
+ }
+ visited.insert({n, true});
+ for (const Node &e : graph.neighbors(n)) {
+ s.push(e);
+ }
+ }
+ }
+}
+
+void Dfs::dfs(const Graph &graph, const Node &start, std::function<bool(const Node&)> func)
+{
+ Data data = { start, func };
+ graph.getData().Accept(static_cast<void*>(&data), DFS);
+}
+
+void Dfs::dfs(const DirectedGraph &graph, const Node &start, std::function<bool(const Node&)> func)
+{
+ dfs_impl(graph, start, func);
+}
+
+void Dfs::dfs(const UndirectedGraph &graph, const Node &start, std::function<bool(const Node&)> func)
+{
+ dfs_impl(graph, start, func);
+}
+
+void Dfs::Visit(void *data, const DirectedGraph &graph) const
+{
+ Data d = *static_cast<Data*>(data);
+ dfs(graph, d.start, d.func);
+}
+
+void Dfs::Visit(void *data, const UndirectedGraph &graph) const
+{
+ Data d = *static_cast<Data*>(data);
+ dfs(graph, d.start, d.func);
+}
+
+const Dfs Dfs::DFS;
+
+} // namespace traverse
+
+} // namespace graph
diff --git a/alib2algo/src/graph/traverse/Dfs.h b/alib2algo/src/graph/traverse/Dfs.h
new file mode 100644
index 0000000000..85fa390ba3
--- /dev/null
+++ b/alib2algo/src/graph/traverse/Dfs.h
@@ -0,0 +1,34 @@
+#ifndef GRAPH_DFS_H_
+#define GRAPH_DFS_H_
+
+#include <graph/Graph.h>
+#include <graph/directed/DirectedGraph.h>
+#include <graph/undirected/UndirectedGraph.h>
+
+namespace graph
+{
+
+namespace traverse
+{
+
+// func is called for each visited node, traversal stops when returning false
+class Dfs : public graph::VisitableGraphBase::const_visitor_type
+{
+public:
+ static void dfs(const Graph &graph, const Node &start, std::function<bool(const Node&)> func);
+
+ static void dfs(const DirectedGraph &graph, const Node &start, std::function<bool(const Node&)> func);
+ static void dfs(const UndirectedGraph &graph, const Node &start, std::function<bool(const Node&)> func);
+
+private:
+ void Visit(void *data, const DirectedGraph &graph) const;
+ void Visit(void *data, const UndirectedGraph &graph) const;
+
+ static const Dfs DFS;
+};
+
+} // namespace traverse
+
+} // namespace graph
+
+#endif // GRAPH_DFS_H_
diff --git a/alib2algo/test-src/graph/traverse/DfsTest.cpp b/alib2algo/test-src/graph/traverse/DfsTest.cpp
new file mode 100644
index 0000000000..f4c8071e83
--- /dev/null
+++ b/alib2algo/test-src/graph/traverse/DfsTest.cpp
@@ -0,0 +1,158 @@
+#include "DfsTest.h"
+
+#include "graph/traverse/Dfs.h"
+
+CPPUNIT_TEST_SUITE_REGISTRATION(GraphDfsTest);
+
+void GraphDfsTest::testTraverseAll()
+{
+ // Common
+ int counter;
+ graph::Node n1("n1");
+ graph::Node n2("n2");
+ graph::Node n3("n3");
+ graph::Node n4("n4");
+ graph::Node n5("n5");
+ graph::Node n6("n6");
+
+ // Directed
+ graph::DirectedGraph dg;
+ dg.addEdge(graph::DirectedEdge(n1, n2));
+ dg.addEdge(graph::DirectedEdge(n1, n2, "multi-edge"));
+ dg.addEdge(graph::DirectedEdge(n2, n3));
+ dg.addEdge(graph::DirectedEdge(n3, n4));
+ dg.addEdge(graph::DirectedEdge(n3, n6));
+ dg.addEdge(graph::DirectedEdge(n4, n1));
+ dg.addEdge(graph::DirectedEdge(n4, n5));
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(dg, n1, [&counter](const graph::Node &) {
+ counter++;
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(6, counter);
+
+ // Undirected
+ graph::UndirectedGraph ug;
+ ug.addEdge(graph::UndirectedEdge(n1, n2));
+ ug.addEdge(graph::UndirectedEdge(n1, n2, "multi-edge"));
+ ug.addEdge(graph::UndirectedEdge(n2, n3));
+ ug.addEdge(graph::UndirectedEdge(n3, n4));
+ ug.addEdge(graph::UndirectedEdge(n3, n6));
+ ug.addEdge(graph::UndirectedEdge(n4, n1));
+ ug.addEdge(graph::UndirectedEdge(n4, n5));
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(ug, n1, [&counter](const graph::Node &) {
+ counter++;
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(6, counter);
+}
+
+void GraphDfsTest::testEarlyReturn()
+{
+ // Common
+ int counter;
+ graph::Node n1("n1");
+ graph::Node n2("n2");
+ graph::Node n3("n3");
+ graph::Node n4("n4");
+
+ // Directed
+ graph::DirectedGraph dg;
+ dg.addEdge(graph::DirectedEdge(n1, n2));
+ dg.addEdge(graph::DirectedEdge(n1, n2, "multi-edge"));
+ dg.addEdge(graph::DirectedEdge(n2, n3));
+ dg.addEdge(graph::DirectedEdge(n3, n4));
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(dg, n1, [&counter](const graph::Node &) {
+ counter++;
+ if (counter == 2) {
+ return false;
+ }
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(2, counter);
+
+ // Undirected
+ graph::UndirectedGraph ug;
+ ug.addEdge(graph::UndirectedEdge(n1, n2));
+ ug.addEdge(graph::UndirectedEdge(n1, n2, "multi-edge"));
+ ug.addEdge(graph::UndirectedEdge(n2, n3));
+ ug.addEdge(graph::UndirectedEdge(n3, n4));
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(ug, n1, [&counter](const graph::Node &) {
+ counter++;
+ if (counter == 2) {
+ return false;
+ }
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(2, counter);
+}
+
+void GraphDfsTest::testDisconnectedGraph()
+{
+ // Common
+ int counter;
+ graph::Node n1("n1");
+ graph::Node n2("n2");
+ graph::Node n3("n3");
+ graph::Node n4("n4");
+ graph::Node n5("n5");
+
+ // Directed
+ graph::DirectedGraph dg;
+ dg.addNode(n5);
+ dg.addEdge(graph::DirectedEdge(n1, n2));
+ dg.addEdge(graph::DirectedEdge(n1, n2, "multi-edge"));
+ dg.addEdge(graph::DirectedEdge(n2, n3));
+ dg.addEdge(graph::DirectedEdge(n3, n4));
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(dg, n1, [&counter](const graph::Node &) {
+ counter++;
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(4, counter);
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(dg, n5, [&counter](const graph::Node &) {
+ counter++;
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(1, counter);
+
+ // Undirected
+ graph::UndirectedGraph ug;
+ ug.addNode(n5);
+ ug.addEdge(graph::UndirectedEdge(n1, n2));
+ ug.addEdge(graph::UndirectedEdge(n1, n2, "multi-edge"));
+ ug.addEdge(graph::UndirectedEdge(n2, n3));
+ ug.addEdge(graph::UndirectedEdge(n3, n4));
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(ug, n1, [&counter](const graph::Node &) {
+ counter++;
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(4, counter);
+
+ counter = 0;
+ graph::traverse::Dfs::dfs(ug, n5, [&counter](const graph::Node &) {
+ counter++;
+ return true;
+ });
+
+ CPPUNIT_ASSERT_EQUAL(1, counter);
+}
diff --git a/alib2algo/test-src/graph/traverse/DfsTest.h b/alib2algo/test-src/graph/traverse/DfsTest.h
new file mode 100644
index 0000000000..c3bf1350e4
--- /dev/null
+++ b/alib2algo/test-src/graph/traverse/DfsTest.h
@@ -0,0 +1,20 @@
+#ifndef DFS_TEST_H_
+#define DFS_TEST_H_
+
+#include <cppunit/extensions/HelperMacros.h>
+
+class GraphDfsTest : public CppUnit::TestFixture
+{
+ CPPUNIT_TEST_SUITE(GraphDfsTest);
+ CPPUNIT_TEST(testTraverseAll);
+ CPPUNIT_TEST(testEarlyReturn);
+ CPPUNIT_TEST(testDisconnectedGraph);
+ CPPUNIT_TEST_SUITE_END();
+
+public:
+ void testTraverseAll();
+ void testEarlyReturn();
+ void testDisconnectedGraph();
+};
+
+#endif // DFS_TEST_H_
--
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