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encompass-cs
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single source longest path

pull/5/head
Evan Hemsley 2019-07-25 20:01:21 -07:00
parent 27c5a9e73e
commit fd43036b2b
2 changed files with 141 additions and 88 deletions
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30
encompass-cs/Graph/DirectedGraph.cs
View File

@ -89,7 +89,7 @@ namespace Encompass
}
}
public void AddEdges(params Tuple<T, T>[] edges)
public void AddEdges(params ValueTuple<T, T>[] edges)
{
foreach (var edge in edges)
{
@ -174,6 +174,34 @@ namespace Encompass
return priority.Values.Reverse();
}
public IEnumerable<ValueTuple<T, int>> LongestPaths(T source)
{
var topoSort = TopologicalSort();
var distances = new Dictionary<T, int>();
foreach (var node in Vertices)
{
distances[node] = int.MaxValue;
}
distances[source] = 0;
foreach (var node in topoSort)
{
if (distances[node] != int.MaxValue)
{
foreach (var neighbor in Neighbors(node))
{
if (distances[neighbor] > distances[node] + 1)
{
distances[neighbor] = distances[node] + 1;
}
}
}
}
return distances.Select((pair) => (pair.Key, pair.Value));
}
public IEnumerable<IEnumerable<T>> StronglyConnectedComponents()
{
var preorder = new Dictionary<T, uint>();

199
test/DirectedGraphTest.cs
View File

@ -47,10 +47,10 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(2, 4),
Tuple.Create(3, 4)
(1, 2),
(2, 3),
(2, 4),
(3, 4)
);
Assert.That(myGraph.Neighbors(1), Does.Contain(2));
@ -66,10 +66,10 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(2, 4),
Tuple.Create(3, 4)
(1, 2),
(2, 3),
(2, 4),
(3, 4)
);
myGraph.RemoveEdge(2, 3);
@ -84,10 +84,10 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(2, 4),
Tuple.Create(3, 4)
(1, 2),
(2, 3),
(2, 4),
(3, 4)
);
myGraph.RemoveVertex(2);
@ -103,9 +103,9 @@ namespace Tests
var myGraph = new DirectedGraph<char>();
myGraph.AddVertices('a', 'b', 'c', 'd');
myGraph.AddEdges(
Tuple.Create('a', 'b'),
Tuple.Create('a', 'c'),
Tuple.Create('b', 'd')
('a', 'b'),
('a', 'c'),
('b', 'd')
);
var result = myGraph.NodeDFS();
@ -129,10 +129,10 @@ namespace Tests
var simpleGraph = new DirectedGraph<char>();
simpleGraph.AddVertices('a', 'b', 'c', 'd');
simpleGraph.AddEdges(
Tuple.Create('a', 'b'),
Tuple.Create('a', 'c'),
Tuple.Create('b', 'a'),
Tuple.Create('b', 'd')
('a', 'b'),
('a', 'c'),
('b', 'a'),
('b', 'd')
);
Assert.That(simpleGraph.TopologicalSort(), Is.EqualTo(new char[] { 'a', 'c', 'b', 'd' }));
@ -144,14 +144,14 @@ namespace Tests
var complexGraph = new DirectedGraph<char>();
complexGraph.AddVertices('a', 'b', 'c', 'd', 'e', 'f', 'g', 't', 'm');
complexGraph.AddEdges(
Tuple.Create('a', 'b'),
Tuple.Create('a', 'c'),
Tuple.Create('a', 'd'),
Tuple.Create('b', 'f'),
Tuple.Create('b', 'g'),
Tuple.Create('c', 'g'),
Tuple.Create('e', 't'),
Tuple.Create('t', 'm')
('a', 'b'),
('a', 'c'),
('a', 'd'),
('b', 'f'),
('b', 'g'),
('c', 'g'),
('e', 't'),
('t', 'm')
);
Assert.That(
@ -160,16 +160,41 @@ namespace Tests
);
}
[Test]
public void LongestPaths()
{
var graph = new DirectedGraph<char>();
graph.AddVertices('r', 's', 't', 'x', 'y', 'z');
graph.AddEdges(
('r', 's'),
('r', 't'),
('s', 'x'),
('s', 't'),
('t', 'y'),
('t', 'x'),
('x', 'y'),
('y', 'z')
);
var result = graph.LongestPaths('r');
result.Should().Contain(('r', 0));
result.Should().Contain(('s', 1));
result.Should().Contain(('t', 1));
result.Should().Contain(('x', 2));
result.Should().Contain(('y', 2));
result.Should().Contain(('z', 3));
}
[Test]
public void StronglyConnectedComponentsSimple()
{
var simpleGraph = new DirectedGraph<int>();
simpleGraph.AddVertices(1, 2, 3);
simpleGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(3, 2),
Tuple.Create(2, 1)
(1, 2),
(2, 3),
(3, 2),
(2, 1)
);
var result = simpleGraph.StronglyConnectedComponents();
@ -185,12 +210,12 @@ namespace Tests
var mediumGraph = new DirectedGraph<int>();
mediumGraph.AddVertices(1, 2, 3, 4);
mediumGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(1, 3),
Tuple.Create(1, 4),
Tuple.Create(4, 2),
Tuple.Create(3, 4),
Tuple.Create(2, 3)
(1, 2),
(1, 3),
(1, 4),
(4, 2),
(3, 4),
(2, 3)
);
var result = mediumGraph.StronglyConnectedComponents();
@ -208,18 +233,18 @@ namespace Tests
var complexGraph = new DirectedGraph<int>();
complexGraph.AddVertices(1, 2, 3, 4, 5, 6, 7, 8);
complexGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(2, 8),
Tuple.Create(3, 4),
Tuple.Create(3, 7),
Tuple.Create(4, 5),
Tuple.Create(5, 3),
Tuple.Create(5, 6),
Tuple.Create(7, 4),
Tuple.Create(7, 6),
Tuple.Create(8, 1),
Tuple.Create(8, 7)
(1, 2),
(2, 3),
(2, 8),
(3, 4),
(3, 7),
(4, 5),
(5, 3),
(5, 6),
(7, 4),
(7, 6),
(8, 1),
(8, 7)
);
var result = complexGraph.StronglyConnectedComponents();
@ -239,11 +264,11 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 1),
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(2, 1),
Tuple.Create(3, 4)
(1, 1),
(1, 2),
(2, 3),
(2, 1),
(3, 4)
);
var clone = myGraph.Clone();
@ -260,11 +285,11 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 1),
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(2, 1),
Tuple.Create(3, 4)
(1, 1),
(1, 2),
(2, 3),
(2, 1),
(3, 4)
);
var subGraph = myGraph.SubGraph(1, 2, 3);
@ -280,13 +305,13 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(0, 1, 2);
myGraph.AddEdges(
Tuple.Create(0, 0),
Tuple.Create(0, 1),
Tuple.Create(0, 2),
Tuple.Create(1, 2),
Tuple.Create(2, 0),
Tuple.Create(2, 1),
Tuple.Create(2, 2)
(0, 0),
(0, 1),
(0, 2),
(1, 2),
(2, 0),
(2, 1),
(2, 2)
);
var result = myGraph.SimpleCycles();
@ -311,20 +336,20 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
myGraph.AddEdges(
Tuple.Create(0, 1),
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(3, 0),
Tuple.Create(0, 3),
Tuple.Create(3, 4),
Tuple.Create(4, 5),
Tuple.Create(5, 0),
Tuple.Create(0, 1),
Tuple.Create(1, 6),
Tuple.Create(6, 7),
Tuple.Create(7, 8),
Tuple.Create(8, 0),
Tuple.Create(8, 9)
(0, 1),
(1, 2),
(2, 3),
(3, 0),
(0, 3),
(3, 4),
(4, 5),
(5, 0),
(0, 1),
(1, 6),
(6, 7),
(7, 8),
(8, 0),
(8, 9)
);
var result = myGraph.SimpleCycles();
@ -348,10 +373,10 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(3, 1),
Tuple.Create(3, 4)
(1, 2),
(2, 3),
(3, 1),
(3, 4)
);
Assert.That(myGraph.Cyclic(), Is.True);
@ -363,9 +388,9 @@ namespace Tests
var myGraph = new DirectedGraph<int>();
myGraph.AddVertices(1, 2, 3, 4);
myGraph.AddEdges(
Tuple.Create(1, 2),
Tuple.Create(2, 3),
Tuple.Create(3, 4)
(1, 2),
(2, 3),
(3, 4)
);
Assert.That(myGraph.Cyclic(), Is.False);