diff --git a/src/content/communitySolutions/12/dalurness.md b/src/content/communitySolutions/12/dalurness.md
new file mode 100644
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+++ b/src/content/communitySolutions/12/dalurness.md
@@ -0,0 +1,71 @@
+---
+descriptions: ["zig"]
+---
+
+## 2025
+
+```zig
+const std = @import("std");
+
+const allocator = std.heap.page_allocator;
+pub fn main() !void {
+    var filename_buf: [16]u8 = undefined;
+    for (0..5) |i| {
+        const filename = try std.fmt.bufPrint(&filename_buf, "./src/input{}.txt", .{i});
+        var file = try std.fs.cwd().openFile(filename, .{ .mode = .read_only });
+        defer file.close();
+        try processFile(&file);
+    }
+}
+fn processFile(file: *std.fs.File) !void {
+    var buf: [1024 * 1024]u8 = undefined;
+    var reader = file.reader(&buf);
+
+    var subs = std.ArrayList(std.ArrayList(u8)).empty;
+    var message = std.ArrayList(u8).empty;
+    while (reader.interface.takeDelimiterExclusive('\n')) |line| {
+        if (std.mem.indexOf(u8, line, &[_]u8{ '=', '>' })) |ind| {
+            const str_start = ind + 4;
+            const str_end = line.len - 1;
+
+            var list = std.ArrayList(u8).empty;
+            try list.append(allocator, line[0]);
+            try list.appendSlice(allocator, line[str_start..str_end]);
+
+            // need to properly replace \n in keys with the actual character for it to work right
+            while (std.mem.indexOf(u8, list.items, &[_]u8{ '\\', 'n' })) |index| {
+                list.orderedRemoveMany(&[_]usize{ index, index + 1 });
+                try list.insert(allocator, index, '\n');
+            }
+
+            try subs.append(allocator, list);
+        } else {
+            try message.appendSlice(allocator, line);
+            try message.append(allocator, '\n');
+        }
+    } else |err| if (err != error.EndOfStream) return err;
+
+    // go through keys in reverse replacing all usages
+    var i: usize = subs.items.len;
+    while (i > 0) : (i -= 1) {
+        const index = i - 1;
+        const char = subs.items[index].items[0];
+        while (std.mem.indexOfScalar(u8, message.items, char)) |ind| {
+            _ = message.orderedRemove(ind);
+            try message.insertSlice(allocator, ind, subs.items[index].items[1..]);
+        }
+    }
+
+    for (message.items) |c| {
+        std.debug.print("{c}", .{c});
+    }
+    std.debug.print("\n\n\n\n======================\n\n\n\n", .{});
+
+    // cleanup
+    for (subs.items) |*list| {
+        list.deinit(allocator);
+    }
+    subs.deinit(allocator);
+    message.deinit(allocator);
+}
+```