From 17a98963986a776df94b80a3787c27505d59fa69 Mon Sep 17 00:00:00 2001 From: Inga Date: Fri, 8 Dec 2023 17:10:30 +0000 Subject: [PATCH] day 8, part 2 (too slow, does not produce an answer) --- day08-hard/build.zig | 70 ++++++++++++++++++ day08-hard/sample.in | 10 +++ day08-hard/src/main.zig | 154 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 234 insertions(+) create mode 100644 day08-hard/build.zig create mode 100644 day08-hard/sample.in create mode 100644 day08-hard/src/main.zig diff --git a/day08-hard/build.zig b/day08-hard/build.zig new file mode 100644 index 0000000..265340e --- /dev/null +++ b/day08-hard/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-hard", + // 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-hard/sample.in b/day08-hard/sample.in new file mode 100644 index 0000000..f84a0c6 --- /dev/null +++ b/day08-hard/sample.in @@ -0,0 +1,10 @@ +LR + +PPA = (PPB, XXX) +PPB = (XXX, PPZ) +PPZ = (PPB, XXX) +QQA = (QQB, XXX) +QQB = (QQC, QQC) +QQC = (QQZ, QQZ) +QQZ = (QQB, QQB) +XXX = (XXX, XXX) \ No newline at end of file diff --git a/day08-hard/src/main.zig b/day08-hard/src/main.zig new file mode 100644 index 0000000..7ce4620 --- /dev/null +++ b/day08-hard/src/main.zig @@ -0,0 +1,154 @@ +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 getMutableSlice(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 FIVE_BITS = 31; +const DEFAULT_NODE_VALUE = (SIXTEEN_BITS << 16) | SIXTEEN_BITS; + +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 = [32 * 32 * 32]usize; + +fn parseNodeNumber(line: []const u8) usize { + var result: usize = 0; + for (line) |char| { + result = (result << 5) + (char - 'A'); + } + + return result; +} + +fn parseNodeLine(line: []const u8, state: *Nodes) void { + const current_node_number = parseNodeNumber(line[0..3]); + state[current_node_number] = (parseNodeNumber(line[7..10]) << 16) | parseNodeNumber(line[12..15]); +} + +fn solve(nodes: Nodes, directions: Directions) usize { + var current = StackList(usize, usize, 1023).init(); + { + var node_number: usize = 0; + while (node_number < nodes.len) : (node_number += 32) { + if (nodes[node_number] != DEFAULT_NODE_VALUE) { + current.add(node_number); + } + } + } + + std.debug.print("Total number of starting points: {d}\n", .{current.length}); + + var i: usize = 0; + while (true) : (i += 1) { + if (i & SIXTEEN_BITS == 0) { + var debug_string = StackList(u8, u8, 255).init(); + for (current.getMutableSlice()) |current_number| { + debug_string.add(@as(u8, @intCast((current_number >> 10) & FIVE_BITS)) + 'A'); + debug_string.add(@as(u8, @intCast((current_number >> 5) & FIVE_BITS)) + 'A'); + debug_string.add(@as(u8, @intCast((current_number >> 0) & FIVE_BITS)) + 'A'); + debug_string.add(' '); + } + std.debug.print("Points at step {d}: {s}\n", .{ i, debug_string.getMutableSlice() }); + } + + var are_all_z = true; + for (current.getMutableSlice()) |*current_number| { + if (current_number.* & FIVE_BITS != 'Z' - 'A') { + are_all_z = false; + } + + const mask = nodes[current_number.*] & directions.getLoopedValue(i); + current_number.* = (mask | (mask >> 16)) & SIXTEEN_BITS; + } + + if (are_all_z) { + break; + } + } + + 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.* = DEFAULT_NODE_VALUE; + } + while (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')) |line| { + parseNodeLine(line, &nodes); + } + + const result = solve(nodes, directions); + try stdout.print("{d}\n", .{result}); +}