func NewLazyPrimMst(g weighted.EdgeWeightedGraph) LazyPrimMst {
l := LazyPrimMst{
marked: make([]bool, g.Vertices()),
mst: collections.Queue{},
pq: collections.PriorityQueue{}}
l.visit(g, 0)
for !l.pq.IsEmpty() {
e := l.pq.DelMin().(*weighted.Edge)
v := e.From()
w := e.OtherVertex(v)
if l.marked[v] && l.marked[w] {
continue
}
l.mst.Push(e)
if !l.marked[v] {
l.visit(g, v)
}
if !l.marked[w] {
l.visit(g, w)
}
}
return l
}
func NewPrimMst(g weighted.EdgeWeightedGraph) PrimMst {
l := PrimMst{
marked: make([]bool, g.Vertices()),
edgeTo: make([]weighted.Edge, g.Vertices()),
distTo: make([]float32, g.Vertices()),
pq: collections.PriorityQueue{}}
for v := 0; v < g.Vertices(); v++ { //initialize all vertice distance weight to maximum
l.distTo[v] = math.MaxFloat32
}
l.distTo[0] = 0.0
vertex := weighted.NewVertex(0, 0.0)
l.pq.Insert(&vertex) //create zero index vertex with zero weight
for !l.pq.IsEmpty() {
vertex := l.pq.DelMin().(collections.IndexItem) // get lowest weight vertice from queue
l.visit(g, vertex.Index())
}
return l
}
func NewDijkstraShortestPaths(g weighted.EdgeWeightedGraph, from int) DijkstraShortestPaths {
l := DijkstraShortestPaths{
edgeTo: make([]weighted.Edge, g.Vertices()),
distTo: make([]float32, g.Vertices()),
pq: collections.PriorityQueue{},
from: from}
for v := 0; v < g.Vertices(); v++ { //initialize all vertice distance weight to maximum
l.distTo[v] = math.MaxFloat32
}
l.distTo[from] = 0.0
vertex := weighted.NewVertex(from, 0.0)
l.pq.Insert(&vertex) //create zero index vertex with zero weight
for l.pq.Len() > 0 {
indexItem := l.pq.DelMin().(collections.IndexItem) // get lowest weight vertice from queue
l.visit(g, indexItem.Index())
}
return l
}
