Setup + Days 1, 2, 3

flake.nix

@@ -0,0 +1,27 @@
+{
+  description = "Advent Of Code 2023";
+
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+
+      forAllSystems = function:
+        nixpkgs.lib.genAttrs [
+          "x86_64-linux"
+          "aarch64-darwin"
+        ] (system: function nixpkgs.legacyPackages.${system});
+
+    in
+      {
+
+        devShells = forAllSystems (pkgs: with pkgs; {
+          default = mkShell {
+            nativeBuildInputs = [ rustc cargo ];
+          };
+        });
+
+      };
+}