advent-of-code/2022/10-cathode-ray-tube/second.zig
2022-12-10 14:23:31 +01:00

38 lines
1.1 KiB
Zig

const std = @import("std");
const input = @embedFile("input");
var result: [6 * 40]u8 = undefined;
pub fn main() anyerror!void {
solve(input);
var y: usize = 0;
while (y < 6) : (y += 1) {
std.debug.print("{s}\n", .{result[y * 40 .. (y + 1) * 40]});
}
}
fn solve(puzzle: []const u8) void {
var it = std.mem.tokenize(u8, puzzle, "\n");
var cycle: usize = 0;
var x: i64 = 1;
var line: []const u8 = undefined;
var prev: ?i64 = null;
// process input
while (cycle < 40 * 6) : (cycle += 1) {
const pos = @mod(cycle, 40);
const draw = pos == x - 1 or pos == x or pos == x + 1;
result[cycle] = if (draw) '#' else '.';
if (prev) |p| { // cpu is busy adding
x += p;
prev = null;
} else { // read another instruction
line = it.next() orelse break;
if (line[0] == 'a') {
var elts = std.mem.split(u8, line, " ");
_ = elts.next() orelse unreachable;
prev = std.fmt.parseInt(i64, elts.next() orelse unreachable, 10) catch unreachable;
}
}
}
}