day-10/internal/one/graph.go

@@ -1,6 +1,7 @@
 package one
 
 import (
+	"slices"
 	"strings"
 )
 
@@ -29,3 +30,11 @@ func (g *graph) isOutOfBounds(p point) bool {
 func (g *graph) valueAt(p point) rune {
 	return rune(g.data[p.y][p.x])
 }
+
+func (g *graph) debug(path []point) string {
+	temp := slices.Clone(g.data)
+	for _, pos := range path {
+		temp[pos.y] = replaceAtIndex(temp[pos.y], '+', pos.x)
+	}
+	return strings.Join(temp, "\n")
+}

day-10/internal/one/util.go

@@ -37,3 +37,9 @@ func parseLines(r io.Reader) (*graph, error) {
 
 	return graph, nil
 }
+
+func replaceAtIndex(s string, r rune, i int) string {
+	out := []rune(s)
+	out[i] = r
+	return string(out)
+}

day-10/internal/two/graph.go

@@ -1,12 +1,14 @@
 package two
 
 import (
+	"slices"
 	"strings"
 )
 
 type point struct {
-	x int
+	x         int
-	y int
+	y         int
+	direction int
 }
 
 type graph struct {
@@ -29,3 +31,11 @@ func (g *graph) isOutOfBounds(p point) bool {
 func (g *graph) valueAt(p point) rune {
 	return rune(g.data[p.y][p.x])
 }
+
+func (g *graph) debug(path []point) string {
+	temp := slices.Clone(g.data)
+	for _, pos := range path {
+		temp[pos.y] = replaceAtIndex(temp[pos.y], '+', pos.x)
+	}
+	return strings.Join(temp, "\n")
+}

day-10/internal/two/neighbours.go

@@ -2,9 +2,9 @@ package two
 
 func neighbours(p point) [4]point {
 	return [4]point{
-		{p.x, p.y - 1},
+		{p.x, p.y - 1, N},
-		{p.x + 1, p.y},
+		{p.x + 1, p.y, E},
-		{p.x, p.y + 1},
+		{p.x, p.y + 1, S},
-		{p.x - 1, p.y},
+		{p.x - 1, p.y, W},
 	}
 }

day-10/internal/two/solve.go

@@ -34,11 +34,15 @@ func Solve(buf []byte) (int, error) {
 				continue
 			}
 
-			for _, n := range neighbours(current) {
+			for dir, n := range neighbours(current) {
 				if graph.isOutOfBounds(n) {
 					continue
 				}
 
+				if n.direction == None {
+					n.direction = dir
+				}
+
 				if graph.valueAt(n)-graph.valueAt(current) == 1 {
 					log.Tracef("pushing %v with value %s back onto the queue\n", n, string(graph.valueAt(n)))
 					queue.Enqueue(n)

day-10/internal/two/util.go

@@ -22,7 +22,7 @@ func parseLines(r io.Reader) (*graph, error) {
 		for _, m := range reStartPos.FindAllStringIndex(line, -1) {
 			graph.startPositions = append(
 				graph.startPositions,
-				point{x: m[0], y: linecount},
+				point{x: m[0], y: linecount, direction: None},
 			)
 		}
 
@@ -37,3 +37,9 @@ func parseLines(r io.Reader) (*graph, error) {
 
 	return graph, nil
 }
+
+func replaceAtIndex(s string, r rune, i int) string {
+	out := []rune(s)
+	out[i] = r
+	return string(out)
+}