feat: solve day 12 and there is no part 2

cmd/12/main_test.go

@@ -6,8 +6,9 @@ import (
 	solution "github.com/StevanFreeborn/advent-of-code-2025/cmd/12"
 )
 
-func TestSolvePartOne(t *testing.T) {
-	expected := -1
+// NOTE: This takes long time
+func TestSolvePartOneWithExampleInput(t *testing.T) {
+	expected := 2
 
 	result := solution.SolvePartOne("EXAMPLE.txt")
 
@@ -15,3 +16,13 @@ func TestSolvePartOne(t *testing.T) {
 		t.Errorf("got %d but wanted %d", result, expected)
 	}
 }
+
+func TestSolvePartOneWithInput(t *testing.T) {
+	expected := 550
+
+	result := solution.SolvePartOne("INPUT.txt")
+
+	if result != expected {
+		t.Errorf("got %d but wanted %d", result, expected)
+	}
+}