2024 day 8 part 1

2024/06/solution.nix

@@ -132,45 +132,56 @@
 
   startingObsMap = getObsMap chart;
 
-  getObsMap = let
-    findObs = lib.lists.findFirstIndex (b: b == "#") null;
-  in chart: chart
+  getObsMap = chart: chart
     |> lib.imap0 (y: line: line
-      |> lib.imap0 (x: char: if char != "#" then null else {
-        right = if y + 1 >= height || x + 1 >= width then null else (chart
-          |> index (y + 1)
-          |> lib.sublist (x + 1) width
-          |> findObs
-          |> maybeAdd (x + 1)
-        );
-        left = if y < 1 || x <= 0 then null else (chart
-          |> index (y - 1)
-          |> lib.sublist 0 (x)
-          |> lib.reverseList
-          |> findObs
-          |> maybeSub (x - 1)
-        );
-        down = if x < 1 then null else (chart
-          |> lib.sublist (y + 1) (height)
-          |> map (index (x - 1))
-          |> findObs
-          |> maybeAdd (y + 1)
-        );
-        up = if x + 1 >= width then null else (searchUp (b: b == "#") {x = x + 1; y = y - 1;} chart);
-      })
+      |> lib.imap0 (x: char: if char != "#" then null else makeObs chart (b: b == "#") {inherit x y;})
     )
   ;
 
-  maybe = f: b: if isNull b then null else f b;
-  maybeAdd = v: builtins.add v |> maybe;
-  maybeSub = v: builtins.sub v |> maybe;
+  makeObs = chart: matcher: {x, y}: {
+    right = if y + 1 >= height || x + 1 >= width then null else 
+      searchRight matcher {x = x + 1; y = y + 1;} chart;
 
-  searchUp = matcher: {x, y}: chart: chart
-    |> lib.sublist 0 (y + 1)
-    |> map (index (x))
+    left = if y < 1 || x <= 0 then null else
+      searchLeft matcher {x = x - 1; y = y - 1;} chart;
+
+    down = if x <= 0 || y + 1 >= width then null else 
+      searchDown matcher {x = x - 1; y = y + 1;} chart;
+
+    up = if x + 1 >= width then null else 
+      searchUp matcher {x = x + 1; y = y - 1;} chart;
+  };
+
+  maybe = f: a: b: if !(builtins.isInt a && builtins.isInt b) then null else f a b;
+  maybeAdd = maybe builtins.add;
+  maybeSub = maybe builtins.sub;
+  column = x: map (index x);
+
+  searchLeft = matcher: {x, y}: chart: chart
+    |> index y
+    |> lib.sublist 0 (x + 1)
     |> lib.reverseList
     |> lib.lists.findFirstIndex matcher null
-    |> maybeSub (y)
+    |> maybeSub x
+  ;
+  searchDown = matcher: {x, y}: chart: chart
+    |> lib.sublist y height
+    |> column x
+    |> lib.lists.findFirstIndex matcher null
+    |> maybeAdd y
+  ;
+  searchRight = matcher: {x, y}: chart: chart
+    |> index y
+    |> lib.sublist x width
+    |> lib.lists.findFirstIndex matcher null
+    |> maybeAdd x
+  ;
+  searchUp = matcher: {x, y}: chart: chart
+    |> lib.sublist 0 (y + 1)
+    |> column x
+    |> lib.reverseList
+    |> lib.lists.findFirstIndex matcher null
+    |> maybeSub y
   ;
 
   firstOb = {
@@ -220,14 +231,46 @@
     x = lib.mod i width;
     y = i / height;
   }) (height * width)
-    |> builtins.filter (pos: index2d pos chart == ".")
-    |> map ({x, y}: replace2d {inherit x y;} "#" chart)
+    |> builtins.filter (pos: index2d pos startingObsMap |> isNull)
+    |> map (pos: insert pos startingObsMap)
   ;
 
-  # this is a really slow way to do this, instead just find the adjacent columns and update accordingly
-  allMaps = allObs |> map getObsMap;
+  replaceColumn = y: lib.zipListsWith (row: new:
+    replace y row new
+  );
 
-  loopyMaps = allMaps
+  insert = {x, y}@pos: chart: let
+    newObs = makeObs chart builtins.isAttrs pos;
+    # nextL = searchRight 
+  in chart
+    |> replace2d pos newObs
+    # update obstacles on rows above and below
+    |> (if y - 1 < 0 then lib.id else nChart: replace (y - 1) (
+        nChart |> index (y - 1)
+          |> lib.imap0 (x: b: if isNull b then null else
+          makeObs nChart builtins.isAttrs {inherit x; y = y - 1;})
+          # |> map (o: if builtins.isAttrs o && o.right > x then
+          #   o // {right = x;} else o)
+      ) nChart)
+    |> (if y + 1 >= width then lib.id else nChart: replace (y + 1) (
+        nChart |> index (y + 1)
+          |> lib.imap0 (x: b: if isNull b then null else
+          makeObs nChart builtins.isAttrs {inherit x; y = y + 1;})
+      ) nChart)
+    |> (if x - 1 < 0 then lib.id else nChart:
+      replaceColumn (x - 1) (column (x - 1) nChart
+        |> lib.imap0 (y: b: if isNull b then null else
+        makeObs nChart builtins.isAttrs {inherit y; x = x - 1;})
+      ) nChart)
+    |> (if x + 1 >= width then lib.id else nChart:
+      replaceColumn (x + 1) (column (x + 1) nChart
+        |> lib.imap0 (y: b: if isNull b then null else
+        makeObs nChart builtins.isAttrs {inherit y; x = x + 1;})
+      ) nChart)
+    
+  ;
+
+  loopyMaps = allObs
     |> builtins.filter (m: (getFastpath {obsMap = m;}).looped);
 
   part2faster = builtins.length loopyMaps;

2024/08/example

@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............

2024/08/input

@@ -0,0 +1,50 @@
+....h.....Q..............Y........................
+...............................Y........C.........
+...............m..........x................B......
+........................Y..............qB.........
+......g4.........................h..Y.....q...c...
+................n.....R...........................
+.......................................w........5.
+........g...m...........................w5........
+..n...........R.1................W.......q.5......
+.........h...n.................e..................
+...............................R..........B....C..
+.........4................................5.e.....
+.......0..4......n.......x..w.....................
+.......g.....m........x..b.....W.....B.......w....
+..............m........................3......C...
+........q...0.......h....................C.3......
+..................3.....................D.........
+...............R..........3.............X.........
+..............................W............k2.....
+..........7............................2..........
+...............A.............................X...2
+.......................c...x......................
+....................................d.............
+.....1......................d.....................
+...........1...........................e..........
+.........0.7K.........................2.........W.
+...b......0.....A.................................
+......................1....ic.....................
+......b......................i....................
+..Q.....b..........................A..E...........
+...7.........................V....................
+........A.....................v......d............
+........v............c...................8E.......
+..............................V........8.....E..N.
+......................6...........................
+.......I....M....................V................
+...G......................a.......8...............
+.........r.9........a...i..................X......
+...............r..i...............e............N..
+.....H...........k....9.....6...............8.....
+.v.....................6................V.........
+.........v.......a........k..........D............
+Ha..........k.........K........E.......d..........
+...............y.MG..............6....D...........
+.........H..G...M......9.K..............N.........
+.......G.........................K................
+...............M.........I.......D................
+..................................................
+....r....y................9.......................
+....y................................N............

2024/08/sample1

@@ -0,0 +1,10 @@
+..........
+...#......
+#.........
+....a.....
+........a.
+.....a....
+..#.......
+......#...
+..........
+..........

2024/08/solution.nix

@@ -0,0 +1,48 @@
+{lib, ...}: let
+
+  addVec = a: b: {x = a.x + b.x; y = a.y + b.y;};
+  subVec = a: b: {x = a.x - b.x; y = a.y - b.y;};
+
+  toCharList = builtins.foldl'
+    ({y, x, chars}: char:
+      if char == "." || char == "#" then {inherit y; x = x + 1; inherit chars;}
+      else if char == "\n" then {y = y + 1; x = 1; inherit chars;}
+      else {inherit y; x = x + 1; chars = chars ++ [{inherit x y char;}];}
+    )
+    {y = 1; x = 1; chars = [];} # yeah starting at 1,1 what you gonna do about it
+  ;
+
+  toNodes = {chars, ...}@amap: amap // {
+    nodes = map (antenna:
+      builtins.foldl' (acc: antenna2:
+        if antenna == antenna2 then acc
+        else if antenna.char != antenna2.char then acc
+        else let
+          delta = subVec antenna antenna2;
+        in acc ++ [(addVec antenna delta)]
+      ) [] chars
+    ) chars;
+  };
+
+  getUniqueNodes = amap: let
+    size = amap.x;
+  in amap.nodes
+      |> lib.concatLists
+      |> builtins.filter ({x, y}: x > 0 && y > 0 && x < size && y < size)
+      |> lib.unique
+  ;
+
+in {
+  inherit addVec subVec toCharList toNodes;
+
+  part1result = s: s
+    |> lib.trim
+    |> lib.stringToCharacters
+    |> toCharList
+    |> toNodes
+    |> getUniqueNodes
+    |> builtins.length
+  ;
+
+
+}

2024/08/solution.test.nix

@@ -0,0 +1,26 @@
+{describe, it, ...}:
+let
+  pkgs = import <nixpkgs> {};
+  solution = import ./solution.nix pkgs;
+  exampleInput = pkgs.lib.readFile ./example;
+  sample1Input = pkgs.lib.readFile ./sample1;
+in [
+  (describe "part 1" [
+    (it "get's the answer with example input" {
+      actual = solution.part1result exampleInput;
+      expected = 14;
+    })
+    (it "get's the answer with other sample" {
+      actual = solution.part1result sample1Input;
+      expected = 4;
+    })
+    (it "adds vectors" {
+      actual = solution.addVec {x = 1; y = 2;} {x = 3; y = 4;};
+      expected = {x = 4; y = 6;};
+    })
+    (it "subtracts vectors" {
+      actual = solution.subVec {x = 4; y = 3;} {x = 1; y = 2;};
+      expected = {x = 3; y = 1;};
+    })
+  ])
+]

2024/flake.nix

@@ -43,5 +43,17 @@
       ];
     };
 
+    day08 = let
+      solution = import ./08/solution.nix pkgs;
+      example = (pkgs.lib.readFile ./08/example);
+      input = (pkgs.lib.readFile ./08/input);
+    in {
+      solution = solution;
+      part1result = solution.part1result input;
+      test = tix.run [
+        ./08/solution.test.nix
+      ];
+    };
+
   };
 }