Nix/2024/01: add solution

Defelo · Dec 1, 2024 · bd2ac09 · bd2ac09
1 parent d4b8e7f
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Showing 4 changed files with 45 additions and 3 deletions.
diff --git a/Nix/2024/01.nix b/Nix/2024/01.nix
@@ -0,0 +1,29 @@
+let
+  lib = import ../lib;
+  inherit (builtins) match fromJSON head sort lessThan length filter;
+  inherit (lib.aoc) input solution;
+  inherit (lib.lists) last zipWith sum;
+  inherit (lib.functions) flip pipe;
+  inherit (lib.math) abs;
+  inherit (lib.strings) splitLines trim;
+
+  sorted = sort lessThan;
+
+  parsed = pipe input [
+    trim
+    splitLines
+    (map (flip pipe [
+      (match " *([0-9]+) *([0-9]+) *")
+      (map fromJSON)
+    ]))
+  ];
+
+  left = map head parsed;
+  right = map last parsed;
+
+  count = x: xs: length (filter (a: a == x) xs);
+in
+  solution {
+    p1 = sum (zipWith (a: b: abs (a - b)) (sorted left) (sorted right));
+    p2 = sum (map (l: l * (count l right)) left);
+  }
diff --git a/Nix/lib/lists.nix b/Nix/lib/lists.nix
@@ -1,5 +1,5 @@
 lib: let
-  inherit (builtins) elemAt length head tail isList concatMap;
+  inherit (builtins) elemAt length head tail isList concatMap foldl' add;
 in rec {
   last = lst: elemAt lst (length lst - 1);
 
@@ -35,4 +35,11 @@ in rec {
     if isList lst
     then concatMap flatten lst
     else [lst];
+
+  zipWith = f: xs: ys:
+    if xs == [] || ys == []
+    then []
+    else [(f (head xs) (head ys))] ++ (zipWith f (tail xs) (tail ys));
+
+  sum = foldl' add 0;
 }
diff --git a/Nix/lib/math.nix b/Nix/lib/math.nix
@@ -0,0 +1,6 @@
+lib: {
+  abs = a:
+    if a < 0
+    then -a
+    else a;
+}
diff --git a/README.md b/README.md
@@ -9,10 +9,10 @@
 |[2021](https://adventofcode.com/2021/leaderboard)|**136**|438|13.41% (of 1014)|0.0532% (of &ge;255548)|
 |[2020](https://adventofcode.com/2020/leaderboard)|**621**|46|65.23% (of 952)|0.3146% (of &ge;197402)|
 
-## [2024](https://adventofcode.com/2024) ([<img height=18 src=".assets/rs.svg"> Rust](Rust/2024): 1/25 | [<img height=18 src=".assets/hs.svg"> Haskell](Haskell/2024): 1/25 | [<img height=18 src=".assets/ua.png"> Uiua](Uiua/2024): 1/25)
+## [2024](https://adventofcode.com/2024) ([<img height=18 src=".assets/rs.svg"> Rust](Rust/2024): 1/25 | [<img height=18 src=".assets/hs.svg"> Haskell](Haskell/2024): 1/25 | [<img height=18 src=".assets/ua.png"> Uiua](Uiua/2024): 1/25 | [<img height=18 src=".assets/nix.svg"> Nix](Nix/2024): 1/25)
 |Mo|Tu|We|Th|Fr|Sa|Su|
 |-|-|-|-|-|-|-|
-|||||||[**1**](https://adventofcode.com/2024/day/1) [<img height=12 src=".assets/rs.svg">](Rust/2024/01.rs "Rust solution for 2024/01") [<img height=12 src=".assets/hs.svg">](Haskell/2024/01.hs "Haskell solution for 2024/01") [<img height=12 src=".assets/ua.png">](https://uiua.org/pad?src=JnNjCgriipwo4oqc4ouV4omgQCAuKeKJoEBcbi4KCuKKgygvK-KJoSjDly8r4oq4PTop4oqZwqR8LyvijLUt4oip4o2GKcKw4oqf4o2JCg== "Uiua solution for 2024/01")|
+|||||||[**1**](https://adventofcode.com/2024/day/1) [<img height=12 src=".assets/rs.svg">](Rust/2024/01.rs "Rust solution for 2024/01") [<img height=12 src=".assets/hs.svg">](Haskell/2024/01.hs "Haskell solution for 2024/01") [<img height=12 src=".assets/ua.png">](https://uiua.org/pad?src=JnNjCgriipwo4oqc4ouV4omgQCAuKeKJoEBcbi4KCuKKgygvK-KJoSjDly8r4oq4PTop4oqZwqR8LyvijLUt4oip4o2GKcKw4oqf4o2JCg== "Uiua solution for 2024/01") [<img height=12 src=".assets/nix.svg">](Nix/2024/01.nix "Nix solution for 2024/01")|
 |[**2**](https://adventofcode.com/2024/day/2)|[**3**](https://adventofcode.com/2024/day/3)|[**4**](https://adventofcode.com/2024/day/4)|[**5**](https://adventofcode.com/2024/day/5)|[**6**](https://adventofcode.com/2024/day/6)|[**7**](https://adventofcode.com/2024/day/7)|[**8**](https://adventofcode.com/2024/day/8)|
 |[**9**](https://adventofcode.com/2024/day/9)|[**10**](https://adventofcode.com/2024/day/10)|[**11**](https://adventofcode.com/2024/day/11)|[**12**](https://adventofcode.com/2024/day/12)|[**13**](https://adventofcode.com/2024/day/13)|[**14**](https://adventofcode.com/2024/day/14)|[**15**](https://adventofcode.com/2024/day/15)|
 |[**16**](https://adventofcode.com/2024/day/16)|[**17**](https://adventofcode.com/2024/day/17)|[**18**](https://adventofcode.com/2024/day/18)|[**19**](https://adventofcode.com/2024/day/19)|[**20**](https://adventofcode.com/2024/day/20)|[**21**](https://adventofcode.com/2024/day/21)|[**22**](https://adventofcode.com/2024/day/22)|