WIP: added container/graph

container/graph/topo.go

@@ -0,0 +1,41 @@
+package sort
+
+// Node is a generic interface representing a graph node.
+type Node[T any] interface {
+	// Value returns the value of the node.
+	Value() T
+	// Adjacencies returns a slice of nodes adjacent to this node
+	Adjacencies() []Node[T]
+}
+
+// Topo performs a topological sort on a slice of nodes in place.
+func TopoSort[T any](nodes []Node[T]) {
+	v := make(map[Node[T]]bool)
+	pos := 0
+	var dfs func(Node[T])
+	dfs = func(n Node[T]) {
+		v[n] = true
+		for _, e := range n.Adjacencies() {
+			if !v[e] {
+				dfs(e)
+			}
+		}
+		nodes[pos] = n
+		pos++
+	}
+
+	for _, n := range nodes {
+		if !v[n] {
+			dfs(n)
+		}
+	}
+}
+
+// RTopoSort performs a reverse topological sort on a slice of nodes in place.
+func RTopoSort[T any](nodes []Node[T]) {
+	TopoSort(nodes)
+
+	for i, j := 0, len(nodes)-1; i < j; i, j = i+1, j-1 {
+		nodes[i], nodes[j] = nodes[j], nodes[i]
+	}
+}