Wow Zig is hard. Day 1 done

README.md

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+# AoC 2023
+
+Doing it in Zig

day1/main.zig

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+const std = @import("std");
+
+pub fn main() !void {
+    const file = try std.fs.cwd().openFile("./data.txt", .{});
+    defer file.close();
+
+    var buffer: [40000]u8 = undefined;
+    _ = try file.readAll(&buffer);
+
+    var it = std.mem.split(u8, &buffer, "\n");
+
+    var total1: u64 = 0;
+    var total2: u64 = 0;
+
+    while (it.next()) |line| {
+        std.debug.print("line: {s}\n", .{line});
+        if (!std.ascii.isAlphanumeric(line[0])) {
+            continue;
+        }
+        var first: ?u8 = null;
+        var last: ?u8 = null;
+
+        // Part 1
+        for (line, 0..) |char, idx| {
+            if (std.ascii.isDigit(char)) {
+                var str = line[idx .. idx + 1];
+                const parsed = try std.fmt.parseInt(u8, str, 10);
+
+                if (first == null) {
+                    first = parsed;
+                }
+                last = parsed;
+            }
+        }
+
+        total1 += (first orelse 0) * 10 + (last orelse 0);
+
+        first = null;
+        last = null;
+
+        // Part 2
+        for (line, 0..) |_, idx| {
+            if (matchDigit(line[idx..line.len])) |parsed| {
+                std.debug.print("parsed: {any}\n", .{parsed});
+
+                if (first == null) {
+                    first = parsed;
+                }
+                last = parsed;
+            }
+        }
+
+        total2 += (first orelse 0) * 10 + (last orelse 0);
+    }
+
+    std.debug.print("part 1 total: {any}\n", .{total1});
+    std.debug.print("part 2 total: {any}\n", .{total2});
+}
+
+pub fn matchDigit(str: []const u8) ?u8 {
+    // is the first char a digit? if so, return it
+    if (std.ascii.isDigit(str[0])) {
+        const digit = std.fmt.parseInt(u8, str[0..1], 10) catch 0;
+        return digit;
+    } else {
+        const words = [_][]const u8{ "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
+
+        for (words, 0..) |word, idx| {
+            if (startsWith(str, word)) {
+                return @intCast(idx + 1);
+            }
+        }
+    }
+
+    return null;
+}
+
+// does the outer string start with the inner string
+pub fn startsWith(outer: []const u8, inner: []const u8) bool {
+    if (outer.len < inner.len) {
+        return false;
+    }
+
+    for (inner, 0..) |c, idx| {
+        if (c != outer[idx]) {
+            return false;
+        }
+    }
+
+    return true;
+}

day1/test.txt

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+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet

day1/test2.txt

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+two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen