From c351b2b2c855f30620c9c9acac2340961baedce5 Mon Sep 17 00:00:00 2001 From: Jeremy Kaplan Date: Sat, 30 Nov 2024 21:32:08 -0800 Subject: [PATCH] 2024 Day 1 --- 2024/.gitignore | 4 +++ 2024/build.zig | 33 ++++++++++++++++++++ 2024/build.zig.zon | 72 +++++++++++++++++++++++++++++++++++++++++++ 2024/src/aoc.zig | 30 ++++++++++++++++++ 2024/src/day01.zig | 76 ++++++++++++++++++++++++++++++++++++++++++++++ README.md | 2 +- 6 files changed, 216 insertions(+), 1 deletion(-) create mode 100644 2024/.gitignore create mode 100644 2024/build.zig create mode 100644 2024/build.zig.zon create mode 100644 2024/src/aoc.zig create mode 100644 2024/src/day01.zig diff --git a/2024/.gitignore b/2024/.gitignore new file mode 100644 index 0000000..6369628 --- /dev/null +++ b/2024/.gitignore @@ -0,0 +1,4 @@ +zig-out +.zig-cache + +/input diff --git a/2024/build.zig b/2024/build.zig new file mode 100644 index 0000000..1387b08 --- /dev/null +++ b/2024/build.zig @@ -0,0 +1,33 @@ +const std = @import("std"); + +// Although this function looks imperative, note that its job is to +// declaratively construct a build graph that will be executed by an external +// runner. +pub fn build(b: *std.Build) void { + // Standard target options allows the person running `zig build` to choose + // what target to build for. Here we do not override the defaults, which + // means any target is allowed, and the default is native. Other options + // for restricting supported target set are available. + const target = b.standardTargetOptions(.{}); + + // Standard optimization options allow the person running `zig build` to select + // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not + // set a preferred release mode, allowing the user to decide how to optimize. + const optimize = b.standardOptimizeOption(.{}); + + // Creates a step for unit testing. This only builds the test executable + // but does not run it. + const lib_unit_tests = b.addTest(.{ + .root_source_file = b.path("src/aoc.zig"), + .target = target, + .optimize = optimize, + }); + + const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests); + + // Similar to creating the run step earlier, this exposes a `test` step to + // the `zig build --help` menu, providing a way for the user to request + // running the unit tests. + const test_step = b.step("test", "Run unit tests"); + test_step.dependOn(&run_lib_unit_tests.step); +} diff --git a/2024/build.zig.zon b/2024/build.zig.zon new file mode 100644 index 0000000..dcf3d03 --- /dev/null +++ b/2024/build.zig.zon @@ -0,0 +1,72 @@ +.{ + // This is the default name used by packages depending on this one. For + // example, when a user runs `zig fetch --save `, this field is used + // as the key in the `dependencies` table. Although the user can choose a + // different name, most users will stick with this provided value. + // + // It is redundant to include "zig" in this name because it is already + // within the Zig package namespace. + .name = "aoc", + + // This is a [Semantic Version](https://semver.org/). + // In a future version of Zig it will be used for package deduplication. + .version = "0.0.0", + + // This field is optional. + // This is currently advisory only; Zig does not yet do anything + // with this value. + //.minimum_zig_version = "0.11.0", + + // This field is optional. + // Each dependency must either provide a `url` and `hash`, or a `path`. + // `zig build --fetch` can be used to fetch all dependencies of a package, recursively. + // Once all dependencies are fetched, `zig build` no longer requires + // internet connectivity. + .dependencies = .{ + // See `zig fetch --save ` for a command-line interface for adding dependencies. + //.example = .{ + // // When updating this field to a new URL, be sure to delete the corresponding + // // `hash`, otherwise you are communicating that you expect to find the old hash at + // // the new URL. + // .url = "https://example.com/foo.tar.gz", + // + // // This is computed from the file contents of the directory of files that is + // // obtained after fetching `url` and applying the inclusion rules given by + // // `paths`. + // // + // // This field is the source of truth; packages do not come from a `url`; they + // // come from a `hash`. `url` is just one of many possible mirrors for how to + // // obtain a package matching this `hash`. + // // + // // Uses the [multihash](https://multiformats.io/multihash/) format. + // .hash = "...", + // + // // When this is provided, the package is found in a directory relative to the + // // build root. In this case the package's hash is irrelevant and therefore not + // // computed. This field and `url` are mutually exclusive. + // .path = "foo", + + // // When this is set to `true`, a package is declared to be lazily + // // fetched. This makes the dependency only get fetched if it is + // // actually used. + // .lazy = false, + //}, + }, + + // Specifies the set of files and directories that are included in this package. + // Only files and directories listed here are included in the `hash` that + // is computed for this package. Only files listed here will remain on disk + // when using the zig package manager. As a rule of thumb, one should list + // files required for compilation plus any license(s). + // Paths are relative to the build root. Use the empty string (`""`) to refer to + // the build root itself. + // A directory listed here means that all files within, recursively, are included. + .paths = .{ + "build.zig", + "build.zig.zon", + "src", + // For example... + //"LICENSE", + //"README.md", + }, +} diff --git a/2024/src/aoc.zig b/2024/src/aoc.zig new file mode 100644 index 0000000..902ef86 --- /dev/null +++ b/2024/src/aoc.zig @@ -0,0 +1,30 @@ +const std = @import("std"); + +pub const Lines = struct { + buf_reader: std.io.BufferedReader(4096, std.fs.File.Reader), + line: std.ArrayList(u8), + + pub fn init(allocator: std.mem.Allocator, file: std.fs.File) Lines { + return .{ + .buf_reader = std.io.bufferedReader(file.reader()), + .line = std.ArrayList(u8).init(allocator), + }; + } + + pub fn deinit(self: Lines) void { + self.line.deinit(); + } + + pub fn next(self: *Lines) !?std.ArrayList(u8) { + const writer = self.line.writer(); + const reader = self.buf_reader.reader(); + + self.line.clearRetainingCapacity(); + if (reader.streamUntilDelimiter(writer, '\n', null)) { + return self.line; + } else |err| switch (err) { + error.EndOfStream => return null, + else => return err, + } + } +}; diff --git a/2024/src/day01.zig b/2024/src/day01.zig new file mode 100644 index 0000000..cf02d55 --- /dev/null +++ b/2024/src/day01.zig @@ -0,0 +1,76 @@ +const std = @import("std"); +const aoc = @import("aoc.zig"); + +pub fn main() !void { + var gpa: std.heap.GeneralPurposeAllocator(.{}) = .{}; + defer _ = gpa.deinit(); + const allocator = gpa.allocator(); + + const file = try std.fs.cwd().openFile("input/day01.txt", .{}); + defer file.close(); + + const stdout_file = std.io.getStdOut().writer(); + var bw = std.io.bufferedWriter(stdout_file); + const stdout = bw.writer(); + + var lines = aoc.Lines.init(allocator, file); + defer lines.deinit(); + + var left = std.ArrayList(u32).init(allocator); + defer left.deinit(); + + var right = std.ArrayList(u32).init(allocator); + defer right.deinit(); + + while (try lines.next()) |line| { + var it = std.mem.tokenizeScalar(u8, line.items, ' '); + const l = it.next().?; + const r = it.next().?; + + try left.append(try std.fmt.parseInt(u32, l, 10)); + try right.append(try std.fmt.parseInt(u32, r, 10)); + } + + std.mem.sort(u32, left.items, {}, comptime std.sort.asc(u32)); + std.mem.sort(u32, right.items, {}, comptime std.sort.asc(u32)); + + try stdout.print("{d}\n", .{part1(left, right)}); + try stdout.print("{d}\n", .{try part2(allocator, left, right)}); + try bw.flush(); +} + +fn part1(left: std.ArrayList(u32), right: std.ArrayList(u32)) u32 { + var i: usize = 0; + var distance: u32 = 0; + while (i < left.items.len) { + distance += abs_diff(left.items[i], right.items[i]); + i += 1; + } + + return distance; +} + +fn abs_diff(a: u32, b: u32) u32 { + if (a > b) { + return a - b; + } else { + return b - a; + } +} + +fn part2(allocator: std.mem.Allocator, left: std.ArrayList(u32), right: std.ArrayList(u32)) !u32 { + var counts = std.AutoHashMap(u32, u32).init(allocator); + defer counts.deinit(); + + for (right.items) |r| { + const v = counts.get(r) orelse 0; + try counts.put(r, v + 1); + } + + var similarity: u32 = 0; + for (left.items) |l| { + similarity += l * (counts.get(l) orelse 0); + } + + return similarity; +} diff --git a/README.md b/README.md index 7f7ad23..625e507 100644 --- a/README.md +++ b/README.md @@ -9,6 +9,7 @@ I like solving the [Advent of Code](https://adventofcode.com/) challenges every - 2021: Go - 2022: Rust (Again! v1.65, 2021 edition) - 2023: Nim +- 2024: Zig Languages I'd like to use for the future or TODO years: - Gleam @@ -16,4 +17,3 @@ Languages I'd like to use for the future or TODO years: - Inko - Koka - Uiua (or other APL-like) -- Zig