Still not solved

16/code.go

@@ -11,6 +11,7 @@ type Point struct {
 	y, x      int
 	cost      int
 	direction []int
+	parent    *Point
 }
 
 func (p *Point) key() string {
@@ -62,7 +63,7 @@ var directions [][]int = [][]int{
 func getMoves(reindeer Point, matrix [][]byte) []Point {
 	var moves []Point
 	for _, direction := range directions {
-		move := Point{x: reindeer.x + direction[0], y: reindeer.y + direction[1], cost: reindeer.cost, direction: direction}
+		move := Point{x: reindeer.x + direction[0], y: reindeer.y + direction[1], cost: reindeer.cost, direction: direction, parent: &reindeer}
 		if matrix[move.y][move.x] != '#' {
 			if reindeer.direction[0] == direction[0] && reindeer.direction[1] == direction[1] {
 				move.cost++
@@ -77,28 +78,49 @@ func getMoves(reindeer Point, matrix [][]byte) []Point {
 	return moves
 }
 
-func hike(reindeer *Point, matrix [][]byte) int {
+func hike(reindeer *Point, matrix [][]byte) (int, []*Point) {
 	cost := 1000000000
 	visited := make(map[string]int)
+	paths := make(map[int][]*Point)
 
 	moves := []Point{*reindeer}
 	for len(moves) > 0 {
 		current := moves[0]
 		moves = moves[1:]
-		if matrix[current.y][current.x] == 'E' && current.cost < cost {
+		if matrix[current.y][current.x] == 'E' && current.cost <= cost {
 			cost = current.cost
+			paths[cost] = append(paths[cost], &current)
 		}
 
 		newMoves := getMoves(current, matrix)
 		for _, newMove := range newMoves {
-			if visited[newMove.key()] == 0 || visited[newMove.key()] > newMove.cost {
+			if visited[newMove.key()] == 0 || visited[newMove.key()] >= newMove.cost {
 				moves = append(moves, newMove)
 				visited[newMove.key()] = newMove.cost
 			}
 		}
 	}
 
-	return cost
+	return cost, paths[cost]
+}
+
+func countTiles(paths []*Point) int {
+	var count int
+	checked := make(map[string]bool)
+
+	for _, path := range paths {
+		current := path
+		for current != nil {
+			if !checked[current.key()] {
+				checked[current.key()] = true
+				count++
+			}
+
+			current = current.parent
+		}
+	}
+
+	return count
 }
 
 func main() {
@@ -113,5 +135,7 @@ func main() {
 	}
 
 	reindeer, matrix := readInput(file)
-	fmt.Println("Part1:", hike(reindeer, matrix))
+	lowestCost, bestPaths := hike(reindeer, matrix)
+	fmt.Println("Part1:", lowestCost)
+	fmt.Println("Part2:", countTiles(bestPaths))
 }