updates

2024/go/utils/dijkstra/queue.go

@@ -0,0 +1,65 @@
+package dijkstra
+
+import "sync"
+
+type NodeQueue struct {
+	Items []Vertex
+	lock  sync.RWMutex
+}
+
+// Enqueue adds an Node to the end of the queue
+func (s *NodeQueue) Enqueue(t Vertex) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	if len(s.Items) == 0 {
+		s.Items = append(s.Items, t)
+		return
+	}
+	var insertFlag bool
+	for k, v := range s.Items {
+		// add vertex distance less than travers's vertex distance
+		if t.Distance < v.Distance {
+			s.Items = append(s.Items[:k+1], s.Items[k:]...)
+			s.Items[k] = t
+			insertFlag = true
+		}
+		if insertFlag {
+			break
+		}
+	}
+	if !insertFlag {
+		s.Items = append(s.Items, t)
+	}
+}
+
+// Dequeue removes an Node from the start of the queue
+func (s *NodeQueue) Dequeue() *Vertex {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	item := s.Items[0]
+	s.Items = s.Items[1:len(s.Items)]
+	return &item
+}
+
+//NewQ Creates New Queue
+func (s *NodeQueue) NewQ() *NodeQueue {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	s.Items = []Vertex{}
+	return s
+}
+
+// IsEmpty returns true if the queue is empty
+func (s *NodeQueue) IsEmpty() bool {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+	return len(s.Items) == 0
+}
+
+// Size returns the number of Nodes in the queue
+func (s *NodeQueue) Size() int {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+	return len(s.Items)
+}