day 1

Author: asmello

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -12,3 +12,8 @@ Cargo.lock
 
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
+
+# Nix
+/target
+result*
+.direnv/

Cargo.lock

@@ -0,0 +1,13 @@
+[package]
+name = "aoc2023"
+version = "0.1.0"
+edition = "2021"
+license = "MIT"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+eyre = "0.6.9"
+
+[dev-dependencies]
+indoc = "2.0.4"

Cargo.toml

@@ -0,0 +1,4 @@
+[licenses]
+allow = [
+  "MIT"
+]

deny.toml

@@ -0,0 +1,139 @@
+{
+  description = "Build a cargo project";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+    crane = {
+      url = "github:ipetkov/crane";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
+    fenix = {
+      url = "github:nix-community/fenix";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.rust-analyzer-src.follows = "";
+    };
+
+    flake-utils.url = "github:numtide/flake-utils";
+
+    advisory-db = {
+      url = "github:rustsec/advisory-db";
+      flake = false;
+    };
+  };
+
+  outputs = { self, nixpkgs, crane, fenix, flake-utils, advisory-db, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+
+        inherit (pkgs) lib;
+
+        craneLib = crane.lib.${system};
+        src = craneLib.cleanCargoSource (craneLib.path ./.);
+
+        # Common arguments can be set here to avoid repeating them later
+        commonArgs = {
+          inherit src;
+          strictDeps = true;
+
+          buildInputs = [
+            # Add additional build inputs here
+          ] ++ lib.optionals pkgs.stdenv.isDarwin [
+            # Additional darwin specific inputs can be set here
+            pkgs.libiconv
+          ];
+
+          # Additional environment variables can be set directly
+          # MY_CUSTOM_VAR = "some value";
+        };
+
+        craneLibLLvmTools = craneLib.overrideToolchain
+          (fenix.packages.${system}.complete.withComponents [
+            "cargo"
+            "llvm-tools"
+            "rustc"
+          ]);
+
+        # Build *just* the cargo dependencies, so we can reuse
+        # all of that work (e.g. via cachix) when running in CI
+        cargoArtifacts = craneLib.buildDepsOnly commonArgs;
+
+        # Build the actual crate itself, reusing the dependency
+        # artifacts from above.
+        my-crate = craneLib.buildPackage (commonArgs // {
+          inherit cargoArtifacts;
+        });
+      in
+      {
+        checks = {
+          # Build the crate as part of `nix flake check` for convenience
+          inherit my-crate;
+
+          # Run clippy (and deny all warnings) on the crate source,
+          # again, resuing the dependency artifacts from above.
+          #
+          # Note that this is done as a separate derivation so that
+          # we can block the CI if there are issues here, but not
+          # prevent downstream consumers from building our crate by itself.
+          my-crate-clippy = craneLib.cargoClippy (commonArgs // {
+            inherit cargoArtifacts;
+            cargoClippyExtraArgs = "--all-targets -- --deny warnings";
+          });
+
+          my-crate-doc = craneLib.cargoDoc (commonArgs // {
+            inherit cargoArtifacts;
+          });
+
+          # Check formatting
+          my-crate-fmt = craneLib.cargoFmt {
+            inherit src;
+          };
+
+          # Audit dependencies
+          my-crate-audit = craneLib.cargoAudit {
+            inherit src advisory-db;
+          };
+
+          # Audit licenses
+          my-crate-deny = craneLib.cargoDeny {
+            inherit src;
+          };
+
+          # Run tests with cargo-nextest
+          # Consider setting `doCheck = false` on `my-crate` if you do not want
+          # the tests to run twice
+          my-crate-nextest = craneLib.cargoNextest (commonArgs // {
+            inherit cargoArtifacts;
+            partitions = 1;
+            partitionType = "count";
+          });
+        };
+
+        packages = {
+          default = my-crate;
+          my-crate-llvm-coverage = craneLibLLvmTools.cargoLlvmCov (commonArgs // {
+            inherit cargoArtifacts;
+          });
+        };
+
+        apps.default = flake-utils.lib.mkApp {
+          drv = my-crate;
+        };
+
+        devShells.default = craneLib.devShell {
+          # Inherit inputs from checks.
+          checks = self.checks.${system};
+
+          # Additional dev-shell environment variables can be set directly
+          # MY_CUSTOM_DEVELOPMENT_VAR = "something else";
+
+          # Extra inputs can be added here; cargo and rustc are provided by default.
+          packages = with pkgs; [
+            # pkgs.ripgrep
+            rust-analyzer
+          ];
+        };
+      });
+}

flake.lock

@@ -0,0 +1,61 @@
+use std::io::{BufRead, BufReader, Read};
+
+use eyre::{eyre, Context};
+
+pub fn part1(input: impl Read) -> eyre::Result<u64> {
+    let reader = BufReader::new(input);
+    let mut sum = 0;
+    for (num, line) in reader.lines().enumerate() {
+        let line = line.wrap_err_with(|| format!("failed to read line {num}"))?;
+        if line.is_empty() {
+            continue;
+        }
+        let (mut first, mut last) = (None, None);
+        for ch in line.chars() {
+            if let Some(digit) = ch.to_digit(10) {
+                first.get_or_insert(digit);
+                last = digit.into();
+            }
+        }
+        let first = first.ok_or_else(|| eyre!("no valid digits in line {num}"))?;
+        let last = last.expect("if first is set, last should be too");
+        sum += 10 * first as u64 + last as u64;
+    }
+    Ok(sum)
+}
+
+// this is dumb, but it's probably the only algorithm that works as intended
+fn replace_in_order(s: &str) -> String {
+    s.replace("one", "one1one")
+        .replace("two", "two2two")
+        .replace("three", "three3three")
+        .replace("four", "four4four")
+        .replace("five", "five5five")
+        .replace("six", "six6six")
+        .replace("seven", "seven7seven")
+        .replace("eight", "eight8eight")
+        .replace("nine", "nine9nine")
+}
+
+pub fn part2(input: impl Read) -> eyre::Result<u64> {
+    let reader = BufReader::new(input);
+    let mut sum = 0;
+    for (num, line) in reader.lines().enumerate() {
+        let line = line.wrap_err_with(|| format!("failed to read line {num}"))?;
+        if line.is_empty() {
+            continue;
+        }
+        let replaced = replace_in_order(&line);
+        let (mut first, mut last) = (None, None);
+        for ch in replaced.chars() {
+            if let Some(digit) = ch.to_digit(10) {
+                first.get_or_insert(digit);
+                last = digit.into();
+            }
+        }
+        let first = first.ok_or_else(|| eyre!("no valid digits in line {num}"))?;
+        let last = last.expect("if first is set, last should be too");
+        sum += 10 * first as u64 + last as u64;
+    }
+    Ok(sum)
+}

flake.nix

@@ -0,0 +1 @@
+pub mod day1;