From 42b55ad2c139559b88aa52fed9bb07db8ad11874 Mon Sep 17 00:00:00 2001 From: Inga Date: Fri, 8 Dec 2023 13:14:20 +0000 Subject: [PATCH] day 8, part 1 --- day08-easy/build.zig | 70 ++++++++++++++++++++++ day08-easy/sample.in | 9 +++ day08-easy/sample2.in | 5 ++ day08-easy/src/main.zig | 128 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 212 insertions(+) create mode 100644 day08-easy/build.zig create mode 100644 day08-easy/sample.in create mode 100644 day08-easy/sample2.in create mode 100644 day08-easy/src/main.zig diff --git a/day08-easy/build.zig b/day08-easy/build.zig new file mode 100644 index 0000000..5100a93 --- /dev/null +++ b/day08-easy/build.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 = "day08-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); +} diff --git a/day08-easy/sample.in b/day08-easy/sample.in new file mode 100644 index 0000000..59e2d47 --- /dev/null +++ b/day08-easy/sample.in @@ -0,0 +1,9 @@ +RL + +AAA = (BBB, CCC) +BBB = (DDD, EEE) +CCC = (ZZZ, GGG) +DDD = (DDD, DDD) +EEE = (EEE, EEE) +GGG = (GGG, GGG) +ZZZ = (ZZZ, ZZZ) \ No newline at end of file diff --git a/day08-easy/sample2.in b/day08-easy/sample2.in new file mode 100644 index 0000000..34ffa8a --- /dev/null +++ b/day08-easy/sample2.in @@ -0,0 +1,5 @@ +LLR + +AAA = (BBB, BBB) +BBB = (AAA, ZZZ) +ZZZ = (ZZZ, ZZZ) \ No newline at end of file diff --git a/day08-easy/src/main.zig b/day08-easy/src/main.zig new file mode 100644 index 0000000..d866be7 --- /dev/null +++ b/day08-easy/src/main.zig @@ -0,0 +1,128 @@ +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: *const Self, needle: T) bool { + for (0..self.length) |i| { + if (self.mem[i] == needle) { + return true; + } + } + + return false; + } + + fn getSlice(self: *Self) []T { + //var mem_full_slice = &self.mem; + //var mem_slice: []T = mem_full_slice[0..self.length]; + //return mem_slice; + return (&self.mem)[0..self.length]; + } + + fn getLoopedValue(self: *const Self, index: usize) T { + return self.mem[index % self.length]; + } + + fn reset(self: *Self) void { + self.length = 0; + } + + fn init() Self { + return Self{ + .mem = undefined, + .length = 0, + }; + } + }; +} + +const SIXTEEN_BITS = 65535; + +const Directions = StackList(usize, usize, 1000); + +fn parseDirections(line: []const u8) Directions { + var result = Directions.init(); + + const left: usize = SIXTEEN_BITS << 16; + const right: usize = SIXTEEN_BITS; + + var index: usize = 0; + while (index < line.len) : (index += 1) { + result.add(switch (line[index]) { + 'L' => left, + 'R' => right, + else => unreachable, + }); + } + + return result; +} + +const Nodes = [26 * 26 * 26]usize; + +fn parseNodeNumber(line: []const u8) usize { + var result: usize = 0; + for (line) |char| { + result = (result * 26) + (char - 'A'); + } + + return result; +} + +fn parseNodeLine(line: []const u8, state: *Nodes) usize { + const current_node_number = parseNodeNumber(line[0..3]); + state[current_node_number] = (parseNodeNumber(line[7..10]) << 16) | parseNodeNumber(line[12..15]); + return current_node_number; +} + +fn solve(nodes: Nodes, directions: Directions, start: usize, end: usize) usize { + var current = start; + var i: usize = 0; + while (current != end) : (i += 1) { + const mask = nodes[current] & directions.getLoopedValue(i); + current = (mask | (mask >> 16)) & SIXTEEN_BITS; + + //if (i % directions.length == 0) { + //std.debug.print("Iteration {d}; current: {d}\n", .{ i, current }); + //} + } + + return i; +} + +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 line_buffer: [1000]u8 = undefined; + const first_line = (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')).?; + var directions = parseDirections(first_line); + _ = try reader.readUntilDelimiterOrEof(&line_buffer, '\n'); + + var nodes: Nodes = undefined; + for (&nodes) |*node| { + node.* = (SIXTEEN_BITS << 16) | SIXTEEN_BITS; + } + const third_line = (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')).?; + const start = parseNodeLine(third_line, &nodes); + _ = start; + var end: usize = 0; + while (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')) |line| { + end = parseNodeLine(line, &nodes); + } + + const result = solve(nodes, directions, 0, nodes.len - 1); + try stdout.print("{d}\n", .{result}); +}