Init

1/solution.nix

@@ -0,0 +1,13 @@
+with import ../utilities.nix;
+
+let
+  input = readFile ./input;
+  elfCalories = map (grp: map toInt (splitString "\n" grp)) (splitString "\n\n" input);
+  totalsPerElf = map sum elfCalories;
+
+  part1 = maxList totalsPerElf;
+  part2 = sum (topOfList (sortList totalsPerElf) 3);
+in {
+  inherit part1;
+  inherit part2;
+}

2/solution.nix

@@ -0,0 +1,35 @@
+with import ../utilities.nix;
+
+let
+  # read file
+  input = readFile ./input;
+  matches = map (line: convertMvId (splitString " " line)) (splitString "\n" input);
+
+  # convert moves to numbers for opponent and player
+  # Rock -> 0, Paper -> 1, Scissors 2
+  mvId = c: m: (charToInt m) - (charToInt c);
+  convertMvId = pair: split pair (a: b: [(mvId "A" a) (mvId "X" b)] );
+
+  # scoring matches
+  isWin = a: b: (mod (a+1) 3) == b;
+  isTie = a: b: a == b;
+  getScore = a: b:
+    b + 1 + # add score for the move itself
+    (if isWin a b then 6
+    else if isTie a b then 3
+    else 0); # loss
+  totalScore = m: sum (map (pair: split pair getScore) m);
+
+  # part 2
+  mkDraw = a: a;
+  mkWin = a: (mod (a+1) 3);
+  mkLoss = a: (mod (a+2) 3);
+  bestMove = a: b:
+    if b == 0 then mkLoss a
+    else if b == 1 then mkDraw a
+    else mkWin a;
+  makeBestMoves = m: map (pair: split pair (a: b: [a (bestMove a b)] )) m;
+in {
+  part1 = totalScore matches;
+  part2 = totalScore (makeBestMoves matches);
+}

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 zuckerberg
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,7 @@
+# AoC 2022 solved using Nix
+
+To evaluate, go to the directory of a day and run:
+
+```sh
+nix eval -f solution.nix
+```

utilities.nix

@@ -0,0 +1,19 @@
+
+let
+  lib = import <nixpkgs/lib>;
+  utils = rec {
+    # Passthrough trace for debugging
+    pTrace = v: lib.traceSeq v v;
+    # find the total sum of a int list
+    sum = l: lib.foldr (x: y: x + y) 0 l;
+    # splits a list of length two into two params then they're passed to a func
+    split = pair: f: f (lib.head pair) (lib.last pair);
+    # Finds the max value in a list
+    maxList = l: lib.foldr lib.max 0 l;
+    # Sorts a int list. Greatest value first
+    sortList = l: lib.sort (x: y: x > y) l;
+    # Returns the top cnt items of the list
+    topOfList = l: cnt: lib.take cnt l;
+  };
+in
+lib // lib.strings // builtins // utils