Impl d1p2 in nix

day1/part2.nix

@@ -0,0 +1,46 @@
+let
+    # Import nixpkgs lib and input file
+    inherit ((builtins.getFlake (builtins.toString ./..)).inputs.nixpkgs) lib;
+    input = builtins.readFile (builtins.toString ./input.txt);
+
+    # Do parsing
+    parsed = ( # Define function to sort lines into two lists
+        lib.lists.foldr
+            (cur: acc: {
+                first = acc.first ++ [(lib.strings.toIntBase10 (builtins.elemAt cur 0))];
+                second = acc.second ++ [(lib.strings.toIntBase10 (builtins.elemAt cur 1))];
+            })
+            { first = []; second = []; }
+    ) ( # Call with input split on newlines and 3 spaces; formatted like [ [ 1 2 ] [ 3 4 ] [ 5 6 ] ]
+        lib.lists.forEach
+            (lib.strings.splitString "\n" input)
+            (e: lib.strings.splitString "   " e)
+    );
+    collapsed = (
+        lib.lists.foldr
+            (cur: acc:
+                acc // (
+                    if (builtins.hasAttr "${builtins.toString cur}" acc)
+                    then {
+                        "${builtins.toString cur}" = acc."${builtins.toString cur}" + 1;
+                    }
+                    else {
+                        "${builtins.toString cur}" = 1;
+                    }
+                )
+            )
+            {}
+    ) parsed.second;
+
+    output = (
+        lib.lists.foldr
+            (cur: acc:
+                acc + (
+                    if (builtins.hasAttr "${builtins.toString cur}" collapsed)
+                    then (cur * collapsed."${builtins.toString cur}")
+                    else 0
+                )
+            )
+            0
+    ) parsed.first;
+in output

deno.lock

@@ -196,6 +196,8 @@
     }
   },
   "remote": {
+    "https://deno.land/std@0.119.0/encoding/hex.ts": "5bc7df19af498c315cdaba69e2fce1b2aef5fc57344e8c21c08991aa8505a260",
+    "https://deno.land/std@0.119.0/hash/md5.ts": "957791b9052b40cfa211eeb755a76ad6ad12177387ba84b47c4bc8be4edd60c8",
     "https://deno.land/x/sqlite@v3.9.1/build/sqlite.js": "2afc7875c7b9c85d89730c4a311ab3a304e5d1bf761fbadd8c07bbdf130f5f9b",
     "https://deno.land/x/sqlite@v3.9.1/build/vfs.js": "7f7778a9fe499cd10738d6e43867340b50b67d3e39142b0065acd51a84cd2e03",
     "https://deno.land/x/sqlite@v3.9.1/mod.ts": "e09fc79d8065fe222578114b109b1fd60077bff1bb75448532077f784f4d6a83",