day 2 part 2

2025/utils.nix

@@ -4,7 +4,7 @@ rec {
   mod = a: b: a - b * (floor (a / b));
   min = a: b: if a < b then a else b;
   max = a: b: if a > b then a else b;
-  split = delim: input: filter (s: isString s && s != "") (split delim input);
+  split = delim: input: filter (s: isString s && s != "") (builtins.split delim input);
   reduce = foldl'; # foldl' (acc: elem: acc + elem) 0 [1 2 3]
   flatten = input: concatMap (x: if isList x then x else [ x ]) input;
   rangeInclusive =
@@ -17,4 +17,29 @@ rec {
       in
       genList (i: min + i) len;
   sum = input: reduce (sum: v: sum + v) 0 input;
+  reverseList =
+    list:
+    if builtins.length list == 0 then
+      [ ]
+    else
+      # Recursively reverse the tail and append the head to the end
+      (reverseList(builtins.tail list)) ++ [ (builtins.head list) ];
+  splitStringByLength =
+    # @param s: The input string.
+    # @param len: The desired length of each part.
+    s: len:
+    let
+      # Recursive helper function
+      splitRec =
+        currentString: acc:
+        if stringLength currentString <= 0 then
+          reverseList acc
+        else
+          let
+            chunk = substring 0 len currentString;
+            remaining = substring len (stringLength currentString - len) currentString;
+          in
+          splitRec remaining ([ chunk ] ++ acc);
+    in
+    splitRec s [ ];
 }