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92 lines
2.3 KiB
Zig
92 lines
2.3 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: [40000]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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std.debug.print("line: {s}\n", .{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 first: ?u8 = null;
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var last: ?u8 = null;
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// Part 1
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for (line, 0..) |char, idx| {
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if (std.ascii.isDigit(char)) {
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var str = line[idx .. idx + 1];
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const parsed = try std.fmt.parseInt(u8, str, 10);
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if (first == null) {
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first = parsed;
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}
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last = parsed;
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}
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}
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total1 += (first orelse 0) * 10 + (last orelse 0);
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first = null;
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last = null;
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// Part 2
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for (line, 0..) |_, idx| {
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if (matchDigit(line[idx..line.len])) |parsed| {
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std.debug.print("parsed: {any}\n", .{parsed});
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if (first == null) {
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first = parsed;
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}
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last = parsed;
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}
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}
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total2 += (first orelse 0) * 10 + (last orelse 0);
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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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pub fn matchDigit(str: []const u8) ?u8 {
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// is the first char a digit? if so, return it
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if (std.ascii.isDigit(str[0])) {
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const digit = std.fmt.parseInt(u8, str[0..1], 10) catch 0;
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return digit;
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} else {
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const words = [_][]const u8{ "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
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for (words, 0..) |word, idx| {
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if (startsWith(str, word)) {
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return @intCast(idx + 1);
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}
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}
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}
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return null;
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}
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// does the outer string start with the inner string
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pub fn startsWith(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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for (inner, 0..) |c, idx| {
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if (c != outer[idx]) {
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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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