day1

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

Day1/1.hs

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+import Lib (calories)
+
+main :: IO ()
+main = print . maximum . calories =<< readFile "input"

Day1/2.hs

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+import Data.List (sortOn)
+import Data.Ord (Down (Down))
+import Lib (calories)
+
+main :: IO ()
+main = print . sum . take 3 . sortOn Down . calories =<< readFile "input"

Day1/Lib.hs

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+module Lib (calories) where
+
+calories :: String -> [Integer]
+calories input =
+  map (sum . map read) $
+    filter (not . null) $ split "" $ split '\n' input
+
+split :: Eq a => a -> [a] -> [[a]]
+split del =
+  foldr
+    ( \c (x : xs) ->
+        if c == del
+          then [] : x : xs
+          else (c : x) : xs
+    )
+    [[]]

flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1669926181,
+        "narHash": "sha256-9UvqeOzNeVj1k3SmsRThcArP/IDos4OA4V38utDx7m8=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "60d042d7e30f35b598d244e2009d4bfc15052e04",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "release-22.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1667395993,
+        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  description = "AoC 2022 in Haskell";
+
+  inputs = {
+    nixpkgs.url = github:nixos/nixpkgs/release-22.05;
+    utils.url = github:numtide/flake-utils;
+  };
+
+  outputs = { self, nixpkgs, utils }:
+    utils.lib.eachDefaultSystem
+      (system:
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+        in
+        {
+          devShells = with pkgs; rec {
+            default = mkShell {
+              buildInputs = [ ghc ];
+            };
+            withLsp = mkShell {
+              buildInputs = [
+                ghc
+                haskell-language-server
+              ];
+            };
+          };
+        }
+      );
+}