157 lines
3.6 KiB
Zig
157 lines
3.6 KiB
Zig
const std = @import("std");
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const print = std.debug.print;
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var file_buf: [140 * 141]u8 = undefined;
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var matrice: [143][143]u8 = undefined;
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const masks = [_][4][4]u8{
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[4][4]u8{
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[4]u8{ ' ', ' ', ' ', ' ' },
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[4]u8{ 'X', 'M', 'A', 'S' },
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[4]u8{ ' ', ' ', ' ', ' ' },
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[4]u8{ ' ', ' ', ' ', ' ' },
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},
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[4][4]u8{
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[4]u8{ ' ', ' ', ' ', ' ' },
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[4]u8{ 'S', 'A', 'M', 'X' },
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[4]u8{ ' ', ' ', ' ', ' ' },
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[4]u8{ ' ', ' ', ' ', ' ' },
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},
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[4][4]u8{
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[4]u8{ ' ', 'X', ' ', ' ' },
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[4]u8{ ' ', 'M', ' ', ' ' },
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[4]u8{ ' ', 'A', ' ', ' ' },
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[4]u8{ ' ', 'S', ' ', ' ' },
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},
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[4][4]u8{
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[4]u8{ ' ', 'S', ' ', ' ' },
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[4]u8{ ' ', 'A', ' ', ' ' },
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[4]u8{ ' ', 'M', ' ', ' ' },
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[4]u8{ ' ', 'X', ' ', ' ' },
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},
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[4][4]u8{
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[4]u8{ 'X', ' ', ' ', ' ' },
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[4]u8{ ' ', 'M', ' ', ' ' },
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[4]u8{ ' ', ' ', 'A', ' ' },
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[4]u8{ ' ', ' ', ' ', 'S' },
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},
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[4][4]u8{
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[4]u8{ 'S', ' ', ' ', ' ' },
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[4]u8{ ' ', 'A', ' ', ' ' },
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[4]u8{ ' ', ' ', 'M', ' ' },
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[4]u8{ ' ', ' ', ' ', 'X' },
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},
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[4][4]u8{
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[4]u8{ ' ', ' ', ' ', 'X' },
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[4]u8{ ' ', ' ', 'M', ' ' },
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[4]u8{ ' ', 'A', ' ', ' ' },
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[4]u8{ 'S', ' ', ' ', ' ' },
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},
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[4][4]u8{
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[4]u8{ ' ', ' ', ' ', 'S' },
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[4]u8{ ' ', ' ', 'A', ' ' },
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[4]u8{ ' ', 'M', ' ', ' ' },
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[4]u8{ 'X', ' ', ' ', ' ' },
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},
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};
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pub fn main() !void {
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const time_start = std.time.microTimestamp();
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setMatrice('.');
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try fillMatrice();
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const total = countMask();
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const time_end = std.time.microTimestamp();
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print("Total time: {d}μs\n", .{time_end - time_start});
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print("Total: {d}\n", .{total});
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}
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fn evaluate(mask: [4][4]u8, sub: [4][4]u8) bool {
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var count: u3 = 0;
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for (mask, sub) |maskX, subX| {
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for (maskX, subX) |maskY, subY| {
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count += if (maskY == subY) 1 else 0;
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}
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}
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return count == 4;
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}
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fn setMatrice(c: u8) void {
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for (0..143) |x| {
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for (0..143) |y| {
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matrice[x][y] = c;
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}
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}
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}
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fn fillMatrice() !void {
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const file = try std.fs.cwd().openFile("day4/input", .{});
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defer file.close();
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_ = try file.readAll(&file_buf);
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var iter = std.mem.split(u8, &file_buf, "\n");
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var x: usize = 1;
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while (iter.next()) |line| {
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defer x += 1;
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for (line, 1..) |c, y| {
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matrice[x][y] = c;
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}
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}
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}
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fn countMask() u32 {
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var total: u32 = 0;
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var iter = MatriceIterator.init();
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while (iter.next()) |sub| {
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for (masks) |mask| {
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total += if (evaluate(mask, sub)) 1 else 0;
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}
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}
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return total;
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}
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const MatriceIterator = struct {
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x: u32 = 0,
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y: u32 = 0,
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return_buf: [4][4]u8 = undefined,
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fn init() MatriceIterator {
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return MatriceIterator{};
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}
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fn next(self: *MatriceIterator) ?[4][4]u8 {
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if (self.x == 139 and self.y == 139) return null;
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self.y += 1;
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if (self.y == 140) {
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self.x += 1;
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self.y = 0;
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}
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for (self.x..(self.x + 4), 0..) |x, a| {
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for (self.y..(self.y + 4), 0..) |y, b| {
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self.return_buf[a][b] = matrice[x][y];
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}
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}
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return self.return_buf;
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}
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};
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test "evaluate" {
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const toEval = [4][4]u8{
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[4]u8{ '.', '.', '.', '.' },
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[4]u8{ 'X', 'M', 'A', 'S' },
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[4]u8{ '.', '.', '.', '.' },
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[4]u8{ '.', '.', '.', '.' },
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};
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try std.testing.expect(evaluate(masks[0], toEval));
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}
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