135 lines
3.7 KiB
Zig
135 lines
3.7 KiB
Zig
const std = @import("std");
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pub fn define_direction(num1: i32, num2: i32) i8 {
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if (num1 > num2) {
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return -1;
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} else if (num2 > num1) {
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return 1;
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} else {
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return 0;
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}
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}
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pub fn part_1() !void {
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var file = try std.fs.cwd().openFile("input.txt", .{});
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defer file.close();
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var buf_reader = std.io.bufferedReader(file.reader());
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var in_stream = buf_reader.reader();
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var safe_reports: u32 = 0;
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var buf: [2048]u8 = undefined;
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while (try in_stream.readUntilDelimiterOrEof(&buf, '\n')) |line| {
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var is_safe = true;
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var first_round = true;
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var last_num: i32 = 0;
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var defined_direction = false;
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var direction: i8 = 0;
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var tokAny = std.mem.tokenizeAny(u8, line, " ");
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while (tokAny.next()) |num| {
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const n = try std.fmt.parseInt(i32, num, 10);
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if (first_round) {
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last_num = n;
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first_round = false;
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continue;
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}
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if (@abs(last_num - n) > 3) {
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is_safe = false;
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break;
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}
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const current_direction = define_direction(last_num, n);
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if (!defined_direction) {
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direction = current_direction;
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defined_direction = true;
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}
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if (current_direction != direction or current_direction == 0) {
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is_safe = false;
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break;
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}
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last_num = n;
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}
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if (is_safe) {
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safe_reports += 1;
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}
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}
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std.debug.print("Part 1: {}\n", .{safe_reports});
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}
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pub fn part_2() !void {
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var file = try std.fs.cwd().openFile("input.txt", .{});
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defer file.close();
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var buf_reader = std.io.bufferedReader(file.reader());
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var in_stream = buf_reader.reader();
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var safe_reports: u32 = 0;
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var buf: [2048]u8 = undefined;
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while (try in_stream.readUntilDelimiterOrEof(&buf, '\n')) |line| {
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var is_safe = true;
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var round: i32 = -1;
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var last_num: i32 = 0;
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var defined_direction = false;
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var direction: i8 = 0;
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var shield = true; // very bad name lol
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var tokAny = std.mem.tokenizeAny(u8, line, " ");
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while (tokAny.next()) |num| {
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round += 1;
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const n = try std.fmt.parseInt(i32, num, 10);
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if (round == 0) {
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defined_direction = false;
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last_num = n;
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continue;
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}
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if (@abs(last_num - n) > 3) {
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if (shield) {
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if (round == 1) {
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defined_direction = false;
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last_num = n;
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}
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shield = false;
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continue;
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}
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is_safe = false;
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break;
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}
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const current_direction = define_direction(last_num, n);
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if (!defined_direction) {
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direction = current_direction;
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if (current_direction != 0) {
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defined_direction = true;
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}
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}
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if (current_direction != direction or current_direction == 0) {
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if (shield) {
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if (round == 2) {
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defined_direction = false;
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last_num = n;
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}
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shield = false;
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continue;
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}
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is_safe = false;
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break;
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}
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last_num = n;
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}
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if (is_safe) {
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safe_reports += 1;
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}
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}
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std.debug.print("Part 2: {}\n", .{safe_reports});
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}
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pub fn main() !void {
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try part_1();
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try part_2();
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}
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