Finish day03, part 1

src/days/day03.zig

@@ -1,7 +1,49 @@
 const std = @import("std");
 
-pub const title = "Day 03";
+pub const title = "Day 03: Lobby";
 
 pub fn run(_: std.mem.Allocator) !void {
+    const input = @embedFile("./input/day03.txt");
+    var lines = std.mem.tokenizeScalar(u8, input, '\n');
+
+    var accumulator: u32 = 0;
+
+    while (lines.next()) |line| {
+        var first_digit: u8 = 0;
+        var first_digit_index: usize = 0;
+        for (line[0..line.len - 1], 0..) |c, i| {
+            const digit = try std.fmt.charToDigit(c, 10);
+            if (digit > first_digit) {
+                first_digit = digit;
+                first_digit_index = i;
+            }
+        }
+        std.debug.print("first = {d}\n", .{first_digit});
+
+        var second_digit: u8 = 0;
+        if (first_digit_index == line.len - 2) {
+            const c = line[line.len - 1];
+            second_digit = try std.fmt.charToDigit(c, 10);
+        } else {
+            for (line[first_digit_index + 1..]) |c| {
+                const digit = try std.fmt.charToDigit(c, 10);
+                if (digit > second_digit) {
+                    second_digit = digit;
+                }
+            }
+        }
+        std.debug.print("second = {d}\n", .{second_digit});
+
+        const joltage = first_digit * 10 + second_digit;
+        accumulator += joltage;
+    }
+
+    var buffer: [8]u8 = undefined;
+    var stdout_writer = std.fs.File.stdout().writer(&buffer);
+    const stdout = &stdout_writer.interface;
+
+    try stdout.print("{d}\n", .{accumulator});
+
+    try stdout.flush();
 }