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119 lines
3.4 KiB
Zig
119 lines
3.4 KiB
Zig
const std = @import("std");
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pub fn main() !void {
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const file = try std.fs.cwd().openFile("./data.txt", .{});
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defer file.close();
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var buffer: [30000]u8 = undefined;
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_ = try file.readAll(&buffer);
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var it = std.mem.split(u8, &buffer, "\n");
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var total1: u64 = 0;
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var total2: u64 = 0;
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while (it.next()) |line| {
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if (!std.ascii.isAlphanumeric(line[0])) {
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continue;
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}
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var game: u64 = 0;
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var busted: bool = false;
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var min_red: u64 = 1;
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var min_green: u64 = 1;
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var min_blue: u64 = 1;
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// Split the row on colons
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var parts = std.mem.split(u8, line, ": ");
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while (parts.next()) |part| {
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// if it contais "Game", parse out the game ID
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if (std.mem.eql(u8, part[0..4], "Game")) {
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game = try std.fmt.parseInt(u8, part[5..], 10);
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} else {
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// Split the turns up by semicolons
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var turns = std.mem.split(u8, part, "; ");
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var red: u64 = 0;
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var green: u64 = 0;
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var blue: u64 = 0;
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while (turns.next()) |turn| {
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// Split the colors up by commas
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var colors = std.mem.split(u8, turn, ", ");
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while (colors.next()) |color| {
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const idx = findIdx(color, ' ').?;
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const num = try std.fmt.parseInt(u8, color[0..idx], 10);
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if (endsWith(color, "red")) {
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if (num > min_red) {
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min_red = num;
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}
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if (num > 12) {
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busted = true;
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}
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red += num;
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} else if (endsWith(color, "green")) {
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if (num > min_green) {
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min_green = num;
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}
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if (num > 13) {
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busted = true;
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}
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green += num;
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} else if (endsWith(color, "blue")) {
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if (num > min_blue) {
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min_blue = num;
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}
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if (num > 14) {
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busted = true;
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}
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blue += num;
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}
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}
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}
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}
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}
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if (!busted) {
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total1 += game;
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}
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const power: u64 = min_red * min_green * min_blue;
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total2 += power;
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}
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std.debug.print("part 1 total: {any}\n", .{total1});
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std.debug.print("part 2 total: {any}\n", .{total2});
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}
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// does the outer string end with the inner string
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fn endsWith(outer: []const u8, inner: []const u8) bool {
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if (outer.len < inner.len) {
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return false;
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}
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const offset = outer.len - inner.len;
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for (inner, 0..) |c, idx| {
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if (c != outer[idx + offset]) {
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return false;
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}
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}
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return true;
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}
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// find the index of char in string
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fn findIdx(string: []const u8, char: u8) ?usize {
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for (string, 0..) |c, idx| {
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if (c == char) {
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return idx;
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}
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}
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return null;
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}
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