d9: python done

2022/d9/.envrc

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+if command -v nix-shell &> /dev/null
+    then
+    use flake
+fi

2022/d9/README.md

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+# Bootstrapping clojure project on 

2022/d9/data/example.txt

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+R 4
+U 4
+L 3
+D 1
+R 4
+D 1
+L 5
+R 2

2022/d9/flake.lock

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+{
+  "nodes": {
+    "flake-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"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1670064435,
+        "narHash": "sha256-+ELoY30UN+Pl3Yn7RWRPabykwebsVK/kYE9JsIsUMxQ=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "61a8a98e6d557e6dd7ed0cdb54c3a3e3bbc5e25c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

2022/d9/flake.nix

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+{
+  description = "D4 AOC with Lua!";
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+  outputs = { nixpkgs, flake-utils, ... } @ inputs:
+    flake-utils.lib.eachSystem flake-utils.lib.defaultSystems (sys:
+      let
+        overlays = [ ];
+        pkgs = import nixpkgs { system = sys; overlays = overlays; };
+        shellHookAfter = ''
+          echo "The input files should be placed under ./data/{submission,example}.txt"
+          echo "This problem shares one input between two parts"
+        '';
+        py_pkgs = [ pkgs.python310 ];
+      in
+      {
+        # Jack of all trades
+        devShell = pkgs.mkShell
+          {
+            nativeBuildInputs = py_pkgs ++ ocaml_pkgs;
+            shellHook = ''
+              echo "> Default runtime. This contains both ocaml and python3 env"
+              echo "Run ./run-py.sh for Python's output and ./run-oml.sh for OCaml's output"
+            '' + shellHookAfter;
+          };
+        devShells = {
+          # nix develop ./#lua
+          # lua = pkgs.mkShell {
+          #   nativeBuildInputs = lua_pkgs;
+          #   shellHook = ''
+          #     echo "> Lua runtime"
+          #     echo "Run ./run-lua.sh to see the output of the solution"
+          #   '' + shellHookAfter;
+          # };
+
+          # nix develop ./#fennel
+
+          # nix develop ./#python
+          python = pkgs.mkShell {
+            nativeBuildInputs = py_pkgs;
+            shellHook = ''
+              echo "> Python3 runtime"
+              echo "Run ./run-py.sh to see the output of the solution"
+            '' + shellHookAfter;
+
+          };
+        };
+      }
+    );
+}

2022/d9/run-py.sh

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+#!/usr/bin/env sh
+echo "example"
+python3 ./src/d9.py ./data/example.txt
+
+echo "submission"
+python3 ./src/d9.py ./data/submission.txt
+

2022/d9/src/d9.py

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+#!/usr/bin/env python3
+import sys
+from typing import Iterable, Generator
+from functools import reduce
+from itertools import product
+
+def add_nd(lhs: Iterable[int], rhs: Iterable[int]):
+    return tuple(l + r for l, r in zip(lhs, rhs))
+def negate_nd(vec: Iterable[int]):
+    return tuple(-e for e in vec)
+def norm_1k_nd(vec: Iterable[int]):
+    return sum(abs(e) for e in vec)
+def norm_infk_nd(vec: Iterable[int]):
+    return max(abs(e) for e in vec)
+
+
+def dir_to_offset(dir: str):
+    match dir:
+        case "U":
+            return (0, 1)
+        case "D":
+            return (0, -1)
+        case "L":
+            return (-1, 0)
+        case "R":
+            return (1, 0)
+        case d:
+            raise RuntimeError(f"Unknown direction {d}")
+def sign(e: int):
+    return 0 if e == 0 else (1 if e > 0 else -1)
+
+def move_knot(knot: list[tuple[int, int]], offset: Iterable[int]):
+    knot.append(add_nd(knot[-1], offset))
+    return knot
+
+def part1(commands: list[tuple[str, int]]):
+    tail_locs: list[tuple[int, int]] = [(0,0)] # keeps track of where tail moved
+    head_locs : list[tuple[int, int]] = [(0,0)] # keeps track of where head moved
+    for dir, rep in commands:
+        for _ in range(rep):
+            move_knot(head_locs, dir_to_offset(dir))
+            offset = add_nd(head_locs[-1], negate_nd(tail_locs[-1]))
+            # print(f"{offset=}")
+            match norm_1k_nd(offset), norm_infk_nd(offset):
+                case (0, _) | (1, _) | (2, 1):
+                    pass # don't need to catchup
+                case (_, _):
+                    # negate & normalize in inf_k
+                    move_knot(tail_locs, (sign(e) for e in offset))
+                case e:
+                    raise RuntimeError(f"Unknown case {e}\n{tail_locs=}\n{head_locs=}")
+    # print(f"{tail_locs=}")
+    # print(f"{head_locs=}")
+
+    return len(set(tail_locs))
+
+def part2(commands: list[tuple[str, int]]):
+    KNOTS = 10
+    locs = [[(0,0)] for _ in range(KNOTS)] # 10 knots :)
+    for dir, rep in commands:
+        for _ in range(rep):
+            move_knot(locs[0], dir_to_offset(dir)) # move head
+            for i in range(1, KNOTS):
+                offset = add_nd(locs[i-1][-1], negate_nd(locs[i][-1]))
+                match norm_1k_nd(offset), norm_infk_nd(offset):
+                    case (0, _) | (1, _) | (2, 1):
+                        pass # don't need to catchup
+                    case (_, _):
+                        # negate & normalize in inf_k
+                        move_knot(locs[i], (sign(e) for e in offset))
+                    case e:
+                        raise RuntimeError(f"Unknown case {e}\n{locs[i]=}\n{locs[i-1]=}")
+    return len(set(locs[-1]))
+
+
+
+def main(lines: Iterable[str]):
+    splited = (line.strip().split() for line in lines)
+    striped_lines = [(comp[0], int(comp[1])) for comp in splited if len(comp) > 0]
+    # print(striped_lines)
+    commands = [(comp[0], int(comp[1])) for comp in striped_lines]
+    print("part1", part1(commands))
+    print("part2", part2(commands))
+    pass
+
+if __name__=="__main__":
+    with open(sys.argv[1], "r") as f:
+        main(f)