func Sort(g *graph.DirGraph) *stack.Stack {
var visit func(v graph.VertexId)
sorted := stack.New()
visited := make(map[graph.VertexId]bool)
marked := make(map[graph.VertexId]bool)
visit = func(v graph.VertexId) {
if marked[v] {
panic("Not a Directed Acyclic Graph (DAG)")
}
marked[v] = true
successors := g.GetSuccessors(v).VerticesIter()
for successor := range successors {
if !marked[successor] && !visited[successor] {
visit(successor)
}
}
visited[v] = true
marked[v] = false
sorted.Push(v)
}
vertices := g.VerticesIter()
for vertex := range vertices {
if !visited[vertex] {
visit(vertex)
}
}
return sorted
}
func DirectedDfs(g *graph.DirGraph, v graph.VertexId, fn func(graph.VertexId)) {
s := stack.New()
s.Push(v)
visited := make(map[graph.VertexId]bool)
for s.Len() > 0 {
v = s.Pop().(graph.VertexId)
if _, ok := visited[v]; !ok {
visited[v] = true
fn(v)
neighbours := g.GetSuccessors(v).VerticesIter()
for neighbour := range neighbours {
s.Push(neighbour)
}
}
}
}
func ShortestPath(g *graph.DirGraph, start graph.VertexId) (dist map[graph.VertexId]int) {
dist = make(map[graph.VertexId]int)
visited := make(map[graph.VertexId]bool)
getDist := func(v graph.VertexId) {
neighbours := g.GetNeighbours(v).VerticesIter()
visited[v] = true
for neighbour := range neighbours {
ok, _ := visited[neighbour]
if !ok {
dist[neighbour] = dist[v] + 1
}
}
}
bfs.Bfs(g, start, getDist)
return
}
func Bfs(g *graph.DirGraph, start graph.VertexId, fn func(graph.VertexId)) {
queue := []graph.VertexId{start}
visited := make(map[graph.VertexId]bool)
var next []graph.VertexId
for len(queue) > 0 {
next = []graph.VertexId{}
for _, vertex := range queue {
visited[vertex] = true
neighbours := g.GetNeighbours(vertex).VerticesIter()
fn(vertex)
for neighbour := range neighbours {
_, ok := visited[neighbour]
if !ok {
next = append(next, neighbour)
}
}
}
queue = next
}
}
func Scc(g *graph.DirGraph) []stack.Stack {
s := stack.New()
n := g.Order()
SCCs := make([]stack.Stack, 0)
visited := make(map[graph.VertexId]bool)
vertices := g.VerticesIter()
for s.Len() != n {
vertex := <-vertices
dfs.DirectedDfs(g, vertex, func(v graph.VertexId) {
if visited[v] == false {
fmt.Println(vertex, v)
s.Push(v)
visited[v] = true
}
})
}
fmt.Println(s)
r := g.Reverse()
visited = make(map[graph.VertexId]bool)
for s.Len() > 0 {
vertex := s.Pop().(graph.VertexId)
scc := stack.New()
if visited[vertex] == false {
dfs.DirectedDfs(r, vertex, func(v graph.VertexId) {
fmt.Println(vertex, v)
if visited[graph.VertexId(v)] == false {
visited[graph.VertexId(v)] = true
fmt.Println(vertex, v)
scc.Push(v)
}
})
}
if scc.Len() > 1 {
SCCs = append(SCCs, *scc)
}
}
return SCCs
}