diff --git a/day10/part2/main.d b/day10/part2/main.d
index 43c9a06..360b714 100644
--- a/day10/part2/main.d
+++ b/day10/part2/main.d
@@ -1,13 +1,25 @@
 import std;
 
+alias Unit = void[0];
+alias Set(T) = Unit[T];
+
+auto toSet(R)(R r)
+{
+    return r.map!(element => tuple(element, Unit.init)).assocArray;
+}
+
+auto setOf(T)(T[] elements...)
+{
+    return elements.toSet;
+}
+
 void main()
 {
-    auto nodes = File("input", "r").byLine.map!(to!int).chain([0])
-        .map!(it => tuple(it, cast(void[0])[])).assocArray;
+    auto nodes = File("input", "r").byLine.map!(to!int).chain([0]).toSet;
     nodes.calculateNumberOfPathsLeadingFromTo(0, nodes.byKey.maxElement).writeln;
 }
 
-ulong calculateNumberOfPathsLeadingFromTo(void[0][int] nodes, int start, int end)
+ulong calculateNumberOfPathsLeadingFromTo(Set!int nodes, int start, int end)
 {
     if (end == start)
     {
@@ -20,14 +32,13 @@ ulong calculateNumberOfPathsLeadingFromTo(void[0][int] nodes, int start, int end
 
 unittest
 {
-    void[0][int] input = [0 : [], 1 : []];
+    Set!int input = setOf(0, 1);
     assert(input.calculateNumberOfPathsLeadingFromTo(0, 1) == 1);
 }
 
 unittest
 {
-    auto input = [16, 10, 15, 5, 1, 11, 7, 19, 6, 12, 4].chain([0])
-        .map!(it => tuple(it, cast(void[0])[])).assocArray;
+    auto input = [16, 10, 15, 5, 1, 11, 7, 19, 6, 12, 4].chain([0]).toSet;
     assert(input.calculateNumberOfPathsLeadingFromTo(0, input.byKey.maxElement) == 8);
 }
 
@@ -36,6 +47,6 @@ unittest
     auto input = [
         28, 33, 18, 42, 31, 14, 46, 20, 48, 47, 24, 23, 49, 45, 19, 38, 39, 11,
         1, 32, 25, 35, 8, 17, 7, 9, 4, 2, 34, 10, 3
-    ].chain([0]).map!(it => tuple(it, cast(void[0])[])).assocArray;
+    ].chain([0]).toSet;
     assert(input.calculateNumberOfPathsLeadingFromTo(0, input.byKey.maxElement) == 19_208);
 }