const std = @import("std"); const moveFnType = *const fn ([]Vector(u8), usize, usize, usize) void; pub fn range(len: usize) []const void { return @as([*]void, undefined)[0..len]; } const lineIter = std.mem.SplitIterator(u8); const Vector = std.ArrayList; // I don't have much time for this, it ain't gonna // be as pretty as the other ones pub fn main() void { var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator); defer arena.deinit(); const allocator = arena.allocator(); const input = @embedFile("input.asc"); std.debug.print("Part 1: {s}\n", .{crane900X(input,moveAppend, allocator)}); std.debug.print("Part 2: {s}\n", .{crane900X(input,moveAppendSlice, allocator)}); } fn crane900X(input: []const u8, moveFn: moveFnType, allocator: std.mem.Allocator) []const u8 { var iter = std.mem.split(u8, input, "\n"); // Parses the header with the states and advances the counter const containers = parseContainers(&iter, allocator); while (iter.next()) |line| { // Not valid if (line.len <= 0) continue; const nums = parseLine(line); moveFn(containers, nums[0], nums[1] - 1, nums[2] - 1); } var res = allocator.alloc(u8, containers.len) catch @panic("Allocation error"); for (containers) |cont, i| { res[i] = cont.items[cont.items.len - 1]; } return res; } fn isNumber(char: u8) bool { return char >= '0' and char <= '9'; } fn isLetter(char: u8) bool { return char >= 'A' and char <= 'Z'; } fn moveAppend(list: []Vector(u8), amount: usize, from: usize, to: usize) void { var i: usize = 0; while (i < amount) : (i += 1) { list[to].append(list[from].pop()) catch @panic("Allocation error"); } } fn moveAppendSlice(list: []Vector(u8), amount: usize, from: usize, to: usize) void { var fromLen = list[from].items.len; list[to].appendSlice(list[from].items[(fromLen - amount)..]) catch @panic("Allocation error"); var i: usize = 0; while (i < amount) : (i += 1) { _ = list[from].pop(); } } fn parseLine(line: []const u8) [3]u8 { var nums = [3]u8{ 0, 0, 0 }; var iter = std.mem.split(u8, line, " "); var i: usize = 0; while (iter.next()) |word| { nums[i] = (std.fmt.parseInt(u8, word, 10) catch continue); i += 1; } return nums; } fn parseContainers(iter: *std.mem.SplitIterator(u8), allocator: std.mem.Allocator) []Vector(u8) { const len = (iter.first().len + 1) / 4; iter.reset(); var containers = Vector(Vector(u8)).init(allocator); var contIdx: usize = 0; while (contIdx < len) : (contIdx += 1) { containers.append(Vector(u8).init(allocator)) catch @panic("Allocation error"); } while (iter.next()) |line| { if (line.len <= 0) continue; // We reached the end if (isNumber(line[1])) { // Consume the next line _ = iter.next(); break; } var i: usize = 0; while (i < len) : (i += 1) { const char = line[i * 4 + 1]; if (!isLetter(char)) continue; containers.items[i].insert(0, char) catch @panic("Allocation error"); } } return containers.items; }