Add Graph.toGraphSortedByEdges: Graph

Author: JavierSegoviaCordoba

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Added
 
+- `Graph.toGraphSortedByEdges: Graph`
+
 ### Changed
 
 ### Deprecated

kotlin-stdlib/api/android/kotlin-stdlib.api

@@ -206,6 +206,7 @@ public abstract interface class com/javiersc/kotlin/stdlib/graph/Graph : java/ut
 	public abstract fun renderer (Lkotlin/jvm/functions/Function1;)V
 	public abstract fun setRenderer (Lkotlin/jvm/functions/Function1;)V
 	public abstract fun toGraph ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
+	public abstract fun toGraphSortedByEdges ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
 	public abstract fun vertexesFor (Ljava/lang/Object;)Ljava/util/List;
 	public abstract fun vertexesFor ([Ljava/lang/Object;)Ljava/util/List;
 }
@@ -222,6 +223,7 @@ public final class com/javiersc/kotlin/stdlib/graph/Graph$DefaultImpls {
 	public static fun getHasMissingVertexes (Lcom/javiersc/kotlin/stdlib/graph/Graph;)Z
 	public static fun renderer (Lcom/javiersc/kotlin/stdlib/graph/Graph;Lkotlin/jvm/functions/Function1;)V
 	public static fun toGraph (Lcom/javiersc/kotlin/stdlib/graph/Graph;)Lcom/javiersc/kotlin/stdlib/graph/Graph;
+	public static fun toGraphSortedByEdges (Lcom/javiersc/kotlin/stdlib/graph/Graph;)Lcom/javiersc/kotlin/stdlib/graph/Graph;
 	public static fun vertexesFor (Lcom/javiersc/kotlin/stdlib/graph/Graph;Ljava/lang/Object;)Ljava/util/List;
 	public static fun vertexesFor (Lcom/javiersc/kotlin/stdlib/graph/Graph;[Ljava/lang/Object;)Ljava/util/List;
 }
@@ -313,6 +315,7 @@ public final class com/javiersc/kotlin/stdlib/graph/MutableGraph : com/javiersc/
 	public fun setRenderer (Lkotlin/jvm/functions/Function1;)V
 	public final fun size ()I
 	public fun toGraph ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
+	public fun toGraphSortedByEdges ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
 	public fun toString ()Ljava/lang/String;
 	public final fun values ()Ljava/util/Collection;
 	public fun vertexesFor (Ljava/lang/Object;)Ljava/util/List;

kotlin-stdlib/api/jvm/kotlin-stdlib.api

@@ -212,6 +212,7 @@ public abstract interface class com/javiersc/kotlin/stdlib/graph/Graph : java/ut
 	public abstract fun renderer (Lkotlin/jvm/functions/Function1;)V
 	public abstract fun setRenderer (Lkotlin/jvm/functions/Function1;)V
 	public abstract fun toGraph ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
+	public abstract fun toGraphSortedByEdges ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
 	public abstract fun vertexesFor (Ljava/lang/Object;)Ljava/util/List;
 	public abstract fun vertexesFor ([Ljava/lang/Object;)Ljava/util/List;
 }
@@ -228,6 +229,7 @@ public final class com/javiersc/kotlin/stdlib/graph/Graph$DefaultImpls {
 	public static fun getHasMissingVertexes (Lcom/javiersc/kotlin/stdlib/graph/Graph;)Z
 	public static fun renderer (Lcom/javiersc/kotlin/stdlib/graph/Graph;Lkotlin/jvm/functions/Function1;)V
 	public static fun toGraph (Lcom/javiersc/kotlin/stdlib/graph/Graph;)Lcom/javiersc/kotlin/stdlib/graph/Graph;
+	public static fun toGraphSortedByEdges (Lcom/javiersc/kotlin/stdlib/graph/Graph;)Lcom/javiersc/kotlin/stdlib/graph/Graph;
 	public static fun vertexesFor (Lcom/javiersc/kotlin/stdlib/graph/Graph;Ljava/lang/Object;)Ljava/util/List;
 	public static fun vertexesFor (Lcom/javiersc/kotlin/stdlib/graph/Graph;[Ljava/lang/Object;)Ljava/util/List;
 }
@@ -319,6 +321,7 @@ public final class com/javiersc/kotlin/stdlib/graph/MutableGraph : com/javiersc/
 	public fun setRenderer (Lkotlin/jvm/functions/Function1;)V
 	public final fun size ()I
 	public fun toGraph ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
+	public fun toGraphSortedByEdges ()Lcom/javiersc/kotlin/stdlib/graph/Graph;
 	public fun toString ()Ljava/lang/String;
 	public final fun values ()Ljava/util/Collection;
 	public fun vertexesFor (Ljava/lang/Object;)Ljava/util/List;

kotlin-stdlib/common/main/kotlin/com/javiersc/kotlin/stdlib/graph/Graph.kt

@@ -61,6 +61,34 @@ public interface Graph<T> : Map<Graph.Vertex<T>, List<Graph.Edge<T>>> {
 
     public fun vertexesFor(vararg values: T): List<T> = values.flatMap(::vertexesFor)
 
+    public fun toGraphSortedByEdges(): Graph<T> = buildGraph {
+        val sortedGraph: MutableGraph<T> = this
+        val graph: Graph<T> = this@Graph
+        val remainingMap: MutableMap<Vertex<T>, List<Edge<T>>> = graph.toMutableMap()
+        while (remainingMap.isNotEmpty()) {
+            val vertexesToBeRemoved: MutableList<Vertex<T>> = mutableListOf()
+            for ((vertex: Vertex<T>, edges: List<Edge<T>>) in remainingMap) {
+                if (edges.isEmpty()) {
+                    sortedGraph.addVertex(vertex.value)
+                    vertexesToBeRemoved.add(vertex)
+                    println()
+                }
+                for (edge: Edge<T> in edges) {
+                    if (edge.destination.value in sortedGraph.keys.map(Vertex<T>::value)) {
+                        sortedGraph.addVertex(edge.source.value)
+                        sortedGraph.addEdge(edge.source.value, edge.destination.value)
+                        vertexesToBeRemoved.add(edge.source)
+                        println()
+                    }
+                }
+            }
+            for (vertexToBeRemoved: Vertex<T> in vertexesToBeRemoved) {
+                remainingMap.remove(vertexToBeRemoved)
+            }
+            vertexesToBeRemoved.clear()
+        }
+    }
+
     public fun renderer(block: Any?.() -> String) {
         this.renderer = block
     }

kotlin-stdlib/common/test/kotlin/com/javiersc/kotlin/stdlib/GraphTest.kt

@@ -310,6 +310,37 @@ class GraphTest {
         assertTrue { graph.vertexesFor(Qux) == listOf(Quux) }
         assertTrue { graph.vertexesFor(Quux) == emptyList<A>() }
     }
+
+    @Test
+    fun vertexes_sorted_by_edges() {
+        val graph: Graph<A> = buildGraph {
+            addVertex(Bar)
+            addVertex(Foo)
+            addVertex(Baz)
+            addEdge(Bar, Baz)
+            addEdge(Foo, Bar)
+        }
+
+        assertTrue {
+            val actual: String = graph.toString()
+            val expect: String = buildString {
+                appendLine("Bar -> [Baz]")
+                appendLine("Foo -> [Bar]")
+                appendLine("Baz -> []")
+            }
+            expect == actual
+        }
+
+        assertTrue {
+            val actual: String = graph.toGraphSortedByEdges().toString()
+            val expect: String = buildString {
+                appendLine("Baz -> []")
+                appendLine("Bar -> [Baz]")
+                appendLine("Foo -> [Bar]")
+            }
+            expect == actual
+        }
+    }
 }
 
 private object Foo : A()