day 4, part 1

main
Inga 🏳‍🌈 12 months ago
parent a9622637d7
commit 076a6da006
  1. 70
      day04-easy/build.zig
  2. 6
      day04-easy/sample.in
  3. 69
      day04-easy/src/main.zig

@ -0,0 +1,70 @@
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(.{});
const exe = b.addExecutable(.{
.name = "day04-easy",
// In this case the main source file is merely a path, however, in more
// complicated build scripts, this could be a generated file.
.root_source_file = .{ .path = "src/main.zig" },
.target = target,
.optimize = optimize,
});
// This declares intent for the executable to be installed into the
// standard location when the user invokes the "install" step (the default
// step when running `zig build`).
b.installArtifact(exe);
// This *creates* a Run step in the build graph, to be executed when another
// step is evaluated that depends on it. The next line below will establish
// such a dependency.
const run_cmd = b.addRunArtifact(exe);
// By making the run step depend on the install step, it will be run from the
// installation directory rather than directly from within the cache directory.
// This is not necessary, however, if the application depends on other installed
// files, this ensures they will be present and in the expected location.
run_cmd.step.dependOn(b.getInstallStep());
// This allows the user to pass arguments to the application in the build
// command itself, like this: `zig build run -- arg1 arg2 etc`
if (b.args) |args| {
run_cmd.addArgs(args);
}
// This creates a build step. It will be visible in the `zig build --help` menu,
// and can be selected like this: `zig build run`
// This will evaluate the `run` step rather than the default, which is "install".
const run_step = b.step("run", "Run the app");
run_step.dependOn(&run_cmd.step);
// Creates a step for unit testing. This only builds the test executable
// but does not run it.
const unit_tests = b.addTest(.{
.root_source_file = .{ .path = "src/main.zig" },
.target = target,
.optimize = optimize,
});
const run_unit_tests = b.addRunArtifact(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_unit_tests.step);
}

@ -0,0 +1,6 @@
Card 1: 41 48 83 86 17 | 83 86 6 31 17 9 48 53
Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
Card 3: 1 21 53 59 44 | 69 82 63 72 16 21 14 1
Card 4: 41 92 73 84 69 | 59 84 76 51 58 5 54 83
Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11

@ -0,0 +1,69 @@
const std = @import("std");
fn StackList(comptime T: type, comptime capacity_type: type, comptime capacity: capacity_type) type {
return struct {
const Self = @This();
mem: [capacity]T,
length: capacity_type,
fn add(self: *Self, value: T) void {
self.mem[self.length] = value;
self.length += 1;
}
fn has(self: *Self, needle: T) bool {
for (0..self.length) |i| {
if (self.mem[i] == needle) {
return true;
}
}
return false;
}
fn init() Self {
return Self{
.mem = undefined,
.length = 0,
};
}
};
}
fn solve(line: []const u8) u32 {
var result: u32 = 0;
var winning_numbers = StackList(u16, u8, 20).init();
var index: usize = 0;
while (index < line.len and line[index] != ':') : (index += 1) {}
index += 2;
while (index < line.len and line[index] != '|') : (index += 3) {
winning_numbers.add((@as(u16, line[index]) << 8) | @as(u16, line[index + 1]));
}
index += 2;
while (index < line.len) : (index += 3) {
const current_card = (@as(u16, line[index]) << 8) | @as(u16, line[index + 1]);
if (winning_numbers.has(current_card)) {
result = if (result == 0) 1 else result * 2;
}
}
return result;
}
pub fn main() !void {
const stdout = std.io.getStdOut().writer();
const raw_in = std.io.getStdIn();
var buffered_reader = std.io.bufferedReader(raw_in.reader());
var reader = buffered_reader.reader();
var result: u32 = 0;
var line_buffer: [1000]u8 = undefined;
while (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')) |line| {
result += solve(line);
}
try stdout.print("{d}\n", .{result});
}
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