Finish day04, part 2

src/days/day04.zig

@@ -1,14 +1,35 @@
 const std = @import("std");
 
-pub const title = "Day 04";
+pub const title = "Day 04: Printing Department";
 
 pub fn run(_: std.mem.Allocator) !void {
-    const input = @embedFile("./input/day04.txt");
-    var lines = std.mem.tokenizeScalar(u8, input, '\n');
+    const initial_input = @embedFile("./input/day04.txt");
+    //const initial_input =
+    //    \\..@@.@@@@.
+    //    \\@@@.@.@.@@
+    //    \\@@@@@.@.@@
+    //    \\@.@@@@..@.
+    //    \\@@.@@@@.@@
+    //    \\.@@@@@@@.@
+    //    \\.@.@.@.@@@
+    //    \\@.@@@.@@@@
+    //    \\.@@@@@@@@.
+    //    \\@.@.@@@.@.
+    //    ;
+
+    const input: []u8 = @constCast(initial_input);
 
     var accumulator: u32 = 0;
 
+    while (true) {
+        std.debug.print("{s}\n", .{input});
+
+        var rolls_removed: u32 = 0;
+
+        var lines = std.mem.tokenizeScalar(u8, input, '\n');
+
         var previous_line: ?[]const u8 = null;
+        var line_index: usize = 0;
         while (lines.next()) |line| {
             const next_line = lines.peek();
 
@@ -36,11 +57,21 @@ pub fn run(_: std.mem.Allocator) !void {
                 }
 
                 if (rolls < 4) {
-                accumulator += 1;
+                    input[(line_index * (line.len + 1)) + i] = 'x';
+                    rolls_removed += 1;
                 }
             }
 
             previous_line = line;
+            line_index += 1;
+        }
+
+        std.debug.print("removed {d} rolls\n", .{rolls_removed});
+        if (rolls_removed > 0) {
+            accumulator += rolls_removed;
+        } else {
+            break;
+        }
     }
 
     var buffer: [8]u8 = undefined;