From 067bb3651b35ee9e3a1e687e8498dda052028245 Mon Sep 17 00:00:00 2001 From: Inga Date: Sun, 3 Dec 2023 15:40:01 +0000 Subject: [PATCH] day 3, part 1 --- day03-easy/build.zig | 70 ++++++++++++++++++++++ day03-easy/sample.in | 10 ++++ day03-easy/src/main.zig | 129 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 209 insertions(+) create mode 100644 day03-easy/build.zig create mode 100644 day03-easy/sample.in create mode 100644 day03-easy/src/main.zig diff --git a/day03-easy/build.zig b/day03-easy/build.zig new file mode 100644 index 0000000..a357166 --- /dev/null +++ b/day03-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 = "day03-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/day03-easy/sample.in b/day03-easy/sample.in new file mode 100644 index 0000000..624ea4f --- /dev/null +++ b/day03-easy/sample.in @@ -0,0 +1,10 @@ +467..114.. +...*...... +..35..633. +......#... +617*...... +.....+.58. +..592..... +......755. +...$.*.... +.664.598.. \ No newline at end of file diff --git a/day03-easy/src/main.zig b/day03-easy/src/main.zig new file mode 100644 index 0000000..3b5f069 --- /dev/null +++ b/day03-easy/src/main.zig @@ -0,0 +1,129 @@ +const std = @import("std"); + +fn isSymbol(char: u8) bool { + return switch (char) { + '0'...'9' => false, + '.' => false, + else => true, + }; +} + +const CharInfo = struct { + adjacents: [8]u8, + this: u8, + + fn isAdjacentToSymbol(self: *const CharInfo) bool { + for (0..8) |i| { + if (isSymbol(self.adjacents[i])) { + return true; + } + } + + return false; + } +}; + +const State = struct { + number: u32 = 0, + is_adjacent_to_symbol: bool = false, + + fn addDigit(self: *State, char_info: CharInfo) void { + self.number = self.number * 10 + (char_info.this - '0'); + self.is_adjacent_to_symbol = self.is_adjacent_to_symbol or char_info.isAdjacentToSymbol(); + } +}; + +fn solve(engine: [][]const CharInfo) u32 { + var result: u32 = 0; + var current_state = State{}; + + for (engine) |line| { + //std.debug.print("handling new line\n", .{}); + for (line) |char_info| { + //std.debug.print("handling: {s}({s})\n", .{ [_]u8{char_info.this}, char_info.adjacents }); + switch (char_info.this) { + '0'...'9' => { + current_state.addDigit(char_info); + }, + else => { + if (current_state.is_adjacent_to_symbol) { + //std.debug.print("adding: {d}\n", .{current_state.number}); + result += current_state.number; + } + + current_state = State{}; + }, + } + } + + if (current_state.is_adjacent_to_symbol) { + //std.debug.print("end of line; adding: {d}\n", .{current_state.number}); + result += current_state.number; + } + + current_state = State{}; + } + + return result; +} + +fn charLinesToCharInfoLines(allocator: std.mem.Allocator, char_lines: [][]const u8) ![][]const CharInfo { + var char_info_lines = try allocator.alloc([]CharInfo, char_lines.len); + for (0..char_lines.len) |i| { + const char_line = char_lines[i]; + var char_info_line = try allocator.alloc(CharInfo, char_line.len); + for (0..char_line.len) |j| { + char_info_line[j] = CharInfo{ .this = char_line[j], .adjacents = .{ + if (i > 0 and j > 0) char_lines[i - 1][j - 1] else '.', + if (i > 0) char_lines[i - 1][j] else '.', + if (i > 0 and j + 1 < char_line.len) char_lines[i - 1][j + 1] else '.', + if (j > 0) char_line[j - 1] else '.', + if (j + 1 < char_line.len) char_line[j + 1] else '.', + if (i + 1 < char_lines.len and j > 0) char_lines[i + 1][j - 1] else '.', + if (i + 1 < char_lines.len) char_lines[i + 1][j] else '.', + if (i + 1 < char_lines.len and j + 1 < char_line.len) char_lines[i + 1][j + 1] else '.', + } }; + } + + char_info_lines[i] = char_info_line; + } + + return char_info_lines; +} + +fn readInput(allocator: std.mem.Allocator, reader: anytype) ![][]const u8 { + var lines = std.ArrayList([]u8).init(allocator); + var line_buffer: [1000]u8 = undefined; + while (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')) |line_ref| { + const line = try allocator.dupe(u8, line_ref); + try lines.append(line); + } + + return lines.items; +} + +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 allocator_buffer: [1_000_000]u8 = undefined; + var fba = std.heap.FixedBufferAllocator.init(&allocator_buffer); + var allocator = fba.allocator(); + + var lines_arena = std.heap.ArenaAllocator.init(allocator); + const lines_allocator = lines_arena.allocator(); + const char_lines = try readInput(lines_allocator, reader); + + var info_lines_arena = std.heap.ArenaAllocator.init(allocator); + const info_lines_allocator = info_lines_arena.allocator(); + const info_lines = try charLinesToCharInfoLines(info_lines_allocator, char_lines); + lines_arena.deinit(); + + const result = solve(info_lines); + info_lines_arena.deinit(); + + try stdout.print("{d}\n", .{result}); +}