Fix Day 21

flake.nix

@@ -19,11 +19,18 @@
 
         devShells = forAllSystems (pkgs: with pkgs; {
           default = mkShell {
-            nativeBuildInputs = [ rustc cargo ];
-            buildInputs = [ hyperfine ];
+            nativeBuildInputs = [ rustc cargo clippy ];
+            buildInputs = [ hyperfine glow libiconv ];
             RUST_SRC_PATH = "${rustPlatform.rustLibSrc}";
+            shellHook = ''
+bench() {
+  cargo build --release
+  DAY=$((($(date +%s)-$(date +%s --date "2023-11-30"))/(3600*24)))
+  hyperfine --parameter-list day $(seq --format "%02.f" 1 $DAY | paste -sd ',' -) "./target/release/day{day} ./data/{day}.in" --runs 20 --warmup 10 --shell=none --export-markdown ./target/bench-output.md 2> /dev/null
+  glow ./target/bench-output.md
+}
+'';
           };
         });
-
       };
 }