dijkstra SSSP

Graph/DirectedGraph.cs

@@ -224,10 +224,10 @@ namespace MoonTools.Core.Graph
             }
             sccs.Clear();
 
-            var preorder = new PooledDictionary<TNode, uint>();
+            var preorder = new PooledDictionary<TNode, uint>(ClearMode.Always);
-            var lowlink = new PooledDictionary<TNode, uint>();
+            var lowlink = new PooledDictionary<TNode, uint>(ClearMode.Always);
-            var sccFound = new PooledDictionary<TNode, bool>();
+            var sccFound = new PooledDictionary<TNode, bool>(ClearMode.Always);
-            var sccQueue = new PooledStack<TNode>();
+            var sccQueue = new PooledStack<TNode>(ClearMode.Always);
 
             uint preorderCounter = 0;
 
@@ -280,7 +280,7 @@ namespace MoonTools.Core.Graph
                             if (lowlink[v] == preorder[v])
                             {
                                 sccFound[v] = true;
-                                var scc = new PooledList<TNode>
+                                var scc = new PooledList<TNode>(ClearMode.Always)
                                 {
                                     v
                                 };

Graph/DirectedWeightedGraph.cs

@@ -112,5 +112,50 @@ namespace MoonTools.Core.Graph
 
             yield break;
         }
+
+        public IEnumerable<(TNode, TNode, int)> DijkstraSingleSourceShortestPath(TNode source)
+        {
+            CheckNodes(source);
+
+            var distance = new PooledDictionary<TNode, int>(ClearMode.Always);
+            var previous = new PooledDictionary<TNode, TNode>(ClearMode.Always);
+
+            foreach (var node in Nodes)
+            {
+                distance[node] = int.MaxValue;
+            }
+
+            distance[source] = 0;
+
+            var q = Nodes.ToPooledList();
+
+            while (q.Count > 0)
+            {
+                var node = q.MinBy(n => distance[n]).First();
+                q.Remove(node);
+                if (distance[node] == int.MaxValue) { break; }
+
+                foreach (var neighbor in Neighbors(node))
+                {
+                    var alt = distance[node] + Weight(node, neighbor);
+                    if (alt < distance[neighbor])
+                    {
+                        distance[neighbor] = alt;
+                        previous[neighbor] = node;
+                    }
+                }
+            }
+
+            foreach (var node in Nodes)
+            {
+                if (!node.Equals(source))
+                {
+                    yield return (node, previous[node], distance[node]);
+                }
+            }
+
+            distance.Dispose();
+            previous.Dispose();
+        }
     }
 }

Graph/UndirectedGraph.cs

@@ -32,9 +32,9 @@ namespace MoonTools.Core.Graph
         {
             get
             {
-                var colors = new PooledDictionary<TNode, Color>();
+                var colors = new PooledDictionary<TNode, Color>(ClearMode.Always);
-                var d = new PooledDictionary<TNode, int>();
+                var d = new PooledDictionary<TNode, int>(ClearMode.Always);
-                var partition = new PooledDictionary<TNode, int>();
+                var partition = new PooledDictionary<TNode, int>(ClearMode.Always);
 
                 foreach (var node in Nodes)
                 {
@@ -48,7 +48,7 @@ namespace MoonTools.Core.Graph
                 partition[start] = 1;
                 d[start] = 0;
 
-                var stack = new PooledStack<TNode>();
+                var stack = new PooledStack<TNode>(ClearMode.Always);
                 stack.Push(start);
 
                 while (stack.Count > 0)

test/DirectedWeightedGraph.cs

@@ -221,5 +221,48 @@ namespace Tests
             // have to call Count() because otherwise the lazy evaluation wont trigger
             myGraph.Invoking(x => x.AStarShortestPath('a', 'z', (x, y) => 1).Count()).Should().Throw<System.ArgumentException>();
         }
+
+        [Test]
+        public void DijkstraSingleSourceShortestPath()
+        {
+            var run = new MoveTypeEdgeData { moveType = MoveType.Run };
+            var jump = new MoveTypeEdgeData { moveType = MoveType.Jump };
+            var wallJump = new MoveTypeEdgeData { moveType = MoveType.WallJump };
+
+            var myGraph = new DirectedWeightedGraph<char, MoveTypeEdgeData>();
+            myGraph.AddNodes('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h');
+            myGraph.AddEdges(
+                ('a', 'b', 2, run),
+                ('a', 'c', 3, run),
+                ('a', 'e', 4, wallJump),
+                ('b', 'd', 2, jump),
+                ('b', 'e', 1, run),
+                ('c', 'g', 4, jump),
+                ('c', 'h', 11, run),
+                ('d', 'c', 3, jump),
+                ('d', 'f', 2, run),
+                ('d', 'h', 3, wallJump),
+                ('e', 'f', 5, run),
+                ('f', 'd', 2, run),
+                ('f', 'h', 6, wallJump),
+                ('g', 'h', 7, run),
+                ('h', 'f', 1, jump)
+            );
+
+            myGraph
+                .DijkstraSingleSourceShortestPath('a')
+                .Should()
+                .Contain(('b', 'a', 2)).And
+                .Contain(('c', 'a', 3)).And
+                .Contain(('d', 'b', 4)).And
+                .Contain(('e', 'b', 3)).And
+                .Contain(('f', 'd', 6)).And
+                .Contain(('g', 'c', 7)).And
+                .Contain(('h', 'd', 7)).And
+                .HaveCount(7);
+
+            // have to call Count() because otherwise the lazy evaluation wont trigger
+            myGraph.Invoking(x => x.DijkstraSingleSourceShortestPath('z').Count()).Should().Throw<System.ArgumentException>();
+        }
     }
 }