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