diff --git a/day-04/internal/one/solve.go b/day-04/internal/one/solve.go
index 773425c..b99f7fb 100644
--- a/day-04/internal/one/solve.go
+++ b/day-04/internal/one/solve.go
@@ -17,13 +17,13 @@ func Solve(buf []byte) (int, error) {
 	wg := sync.WaitGroup{}
 	sumChan := make(chan bool)
 
-	for i := 0; i < len(graph.data); i++ {
-		for j := 0; j < len(graph.data[i]); j++ {
+	for y := range graph.data {
+		for x := range graph.data[y] {
 			wg.Add(1)
 			go func() {
 				defer wg.Done()
 
-				current := newPoint(j, i)
+				current := newPoint(x, y)
 				if graph.valueAt(current) == 'X' {
 					for _, n := range neighbours(current) {
 						sumChan <- checkNeighbours(n, "MAS", graph)
diff --git a/day-04/internal/two/solve.go b/day-04/internal/two/solve.go
index 2fd1351..548d11c 100644
--- a/day-04/internal/two/solve.go
+++ b/day-04/internal/two/solve.go
@@ -16,13 +16,13 @@ func Solve(buf []byte) (int, error) {
 	wg := sync.WaitGroup{}
 	sumChan := make(chan bool)
 
-	for i := 0; i < len(graph.data); i++ {
-		for j := 0; j < len(graph.data[i]); j++ {
+	for y := range graph.data {
+		for x := range graph.data[y] {
 			wg.Add(1)
 			go func() {
 				defer wg.Done()
 
-				current := newPoint(j, i)
+				current := newPoint(x, y)
 				if graph.valueAt(current) == 'A' {
 					if func() bool {
 						for _, n := range neighbours(current) {
diff --git a/day-12/internal/one/solve.go b/day-12/internal/one/solve.go
index b03850b..e70d710 100644
--- a/day-12/internal/one/solve.go
+++ b/day-12/internal/one/solve.go
@@ -15,9 +15,9 @@ func Solve(buf []byte) (int, error) {
 
 	var totalCost int
 	totalAreaVisited := make(map[point]struct{})
-	for i := 0; i < len(graph.data); i++ {
-		for j := 0; j < len(graph.data[i]); j++ {
-			start := newPoint(j, i)
+	for y := range graph.data {
+		for x := range graph.data[y] {
+			start := newPoint(x, y)
 			if graph.isOutOfBounds(start) {
 				continue
 			}
diff --git a/day-12/internal/two/solve.go b/day-12/internal/two/solve.go
index 90e9772..6f05422 100644
--- a/day-12/internal/two/solve.go
+++ b/day-12/internal/two/solve.go
@@ -15,9 +15,9 @@ func Solve(buf []byte) (int, error) {
 
 	var totalCost int
 	totalAreaVisited := make(map[point]struct{})
-	for i := 0; i < len(graph.data); i++ {
-		for j := 0; j < len(graph.data[i]); j++ {
-			start := newPoint(j, i)
+	for y := range graph.data {
+		for x := range graph.data[y] {
+			start := newPoint(x, y)
 			if graph.isOutOfBounds(start) {
 				continue
 			}