day-15/internal/two/explore.go

@@ -6,24 +6,24 @@ import (
 	orderedmap "github.com/wk8/go-ordered-map/v2"
 )
 
-func exploreDFS(graph *graph, next point, dir direction, stack *stack) (*stack, bool) {
+func exploreDFS(graph *graph, next point, direction direction, stack *stack) (*stack, bool) {
 	ns := neighbours(next)
 
-	log.Debug(string(graph.valueAt(ns[dir])))
+	log.Debug(string(graph.valueAt(ns[direction])))
 
-	switch graph.valueAt(ns[dir]) {
+	switch graph.valueAt(ns[direction]) {
 	case '#':
 		return nil, false
 	case '.':
 		return stack, true
 	case '[', ']':
-		stack.Push(ns[dir])
+		stack.Push(ns[direction])
 	}
 
-	return exploreDFS(graph, ns[dir], dir, stack)
+	return exploreDFS(graph, ns[direction], direction, stack)
 }
 
-func exploreBFS(graph *graph, dir direction) (*orderedmap.OrderedMap[point, struct{}], bool) {
+func exploreBFS(graph *graph, direction direction) (*orderedmap.OrderedMap[point, struct{}], bool) {
 	queue := newQueue()
 	queue.Enqueue(graph.robot)
 	visited := make(map[point]struct{})
@@ -39,38 +39,60 @@ func exploreBFS(graph *graph, dir direction) (*orderedmap.OrderedMap[point, stru
 		visited[current] = struct{}{}
 
 		ns := neighbours(current)
-		switch graph.valueAt(ns[dir]) {
+		switch graph.valueAt(ns[direction]) {
 		case '.':
 			if graph.valueAt(current) == '@' {
 				return om, true
 			}
 		case '#':
 			return om, false
-		case '[', ']':
-			nextDirections := []direction{dir}
+		case '[':
+			log.Debugf("adding %s to the queue", string(graph.valueAt(ns[direction])))
+			queue.Enqueue(ns[direction])
+			_, ok := om.Get(ns[direction])
+			if !ok {
+				om.Set(ns[direction], struct{}{})
+			}
 
-			if graph.valueAt(ns[dir]) == '[' {
-				switch dir {
-				case N:
-					nextDirections = append(nextDirections, NE)
-				case S:
-					nextDirections = append(nextDirections, SE)
+			switch direction {
+			case N:
+				log.Debugf("adding %s to the queue", string(graph.valueAt(ns[NE])))
+				queue.Enqueue(ns[NE])
+				_, ok := om.Get(ns[NE])
+				if !ok {
+					om.Set(ns[NE], struct{}{})
 				}
-			} else if graph.valueAt(ns[dir]) == ']' {
-				switch dir {
-				case N:
-					nextDirections = append(nextDirections, NW)
-				case S:
-					nextDirections = append(nextDirections, SW)
+			case S:
+				log.Debugf("adding %s to the queue", string(graph.valueAt(ns[SE])))
+				queue.Enqueue(ns[SE])
+				_, ok := om.Get(ns[SE])
+				if !ok {
+					om.Set(ns[SE], struct{}{})
 				}
 			}
 
-			for _, nextDirection := range nextDirections {
-				log.Debugf("adding %s to the queue", string(graph.valueAt(ns[nextDirection])))
-				queue.Enqueue(ns[nextDirection])
-				_, ok := om.Get(ns[nextDirection])
+		case ']':
+			log.Debugf("adding %s to the queue", string(graph.valueAt(ns[direction])))
+			queue.Enqueue(ns[direction])
+			_, ok := om.Get(ns[direction])
+			if !ok {
+				om.Set(ns[direction], struct{}{})
+			}
+
+			switch direction {
+			case N:
+				log.Debugf("adding %s to the queue", string(graph.valueAt(ns[NW])))
+				queue.Enqueue(ns[NW])
+				_, ok := om.Get(ns[NW])
 				if !ok {
-					om.Set(ns[nextDirection], struct{}{})
+					om.Set(ns[NW], struct{}{})
+				}
+			case S:
+				log.Debugf("adding %s to the queue", string(graph.valueAt(ns[SW])))
+				queue.Enqueue(ns[SW])
+				_, ok := om.Get(ns[SW])
+				if !ok {
+					om.Set(ns[SW], struct{}{})
 				}
 			}
 		}