func addMinPathLeft(graph *m.Graph) {
dp := &m.DijkstraPrio{}
heap.Init(dp)
visited := make(map[*m.Node]bool)
endNode := graph.EndNode()
endNode.SetMinPathLeft(0)
visited[endNode] = true
for _, edge := range endNode.ToEdges() {
node := edge.From()
node.SetMinPathLeft(edge.FastestTime())
heap.Push(dp, node)
}
if dp.Len() > 0 {
for node := heap.Pop(dp).(*m.Node); dp.Len() > 0; node = heap.Pop(dp).(*m.Node) {
visited[node] = true
for _, edge := range node.ToEdges() {
innerNode := edge.From()
if !visited[innerNode] {
innerNode.SetMinPathLeft(edge.FastestTime() + node.MinPathLeft())
heap.Push(dp, innerNode)
}
}
}
}
}
// Route takes a created graph object and finds the shortest path from start to end, returning
// that path as a list of edges.
func Route(graph *m.Graph) []*m.Edge {
if graph.StartNode() == nil || graph.EndNode() == nil {
return nil
}
addMinPathLeft(graph)
startPath := m.CreatePath()
startPath.AddRewards(graph.StartNode().Rewards())
pq := &m.PrioQueue{}
heap.Init(pq)
addNodeEdgesToPrioQueue(pq, graph.StartNode(), startPath)
for path := prioPath(pq); path != nil; path = prioPath(pq) {
node := path.Edges()[len(path.Edges())-1].To()
if node == graph.EndNode() {
return path.Edges()
}
addNodeEdgesToPrioQueue(pq, node, path)
}
return nil
}
