1 files changed, 59 insertions, 0 deletions
diff --git a/src/day-4/part-2.zig b/src/day-4/part-2.zig
new file mode 100644
index 0000000..a6793d7
--- /dev/null
+++ b/src/day-4/part-2.zig
@@ -0,0 +1,59 @@
+const std = @import("std");
+
+pub fn adj(list: std.ArrayList([]u8), x: usize, y: usize) u8 {
+    var count: u8 = 0;
+
+    if(y > 0 and list.items[y - 1][x] == '@') count += 1;
+    if(y < list.items.len - 1 and list.items[y + 1][x] == '@') count += 1;
+    if(x > 0 and list.items[y][x - 1] == '@') count += 1;
+    if(x < list.items[0].len - 1 and list.items[y][x + 1] == '@') count += 1;
+
+    if(y > 0 and x > 0 and list.items[y - 1][x - 1] == '@') count += 1;
+    if(y < list.items.len - 1 and x > 0 and list.items[y + 1][x - 1] == '@') count += 1;
+    if(y > 0 and x < list.items[0].len - 1 and list.items[y - 1][x + 1] == '@') count += 1;
+    if(y < list.items.len - 1 and x < list.items[0].len - 1 and list.items[y + 1][x + 1] == '@') count += 1;
+
+    return count;
+}
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const alloc = gpa.allocator();
+    
+    const path = "input.txt";
+    const fp = try std.fs.cwd().openFile(path, .{.mode = std.fs.File.OpenMode.read_only});
+    defer fp.close();
+    var reader = fp.reader();
+
+    var buffer: [256]u8 = undefined;
+    var list = std.ArrayList([]u8).init(alloc);
+    defer list.deinit();
+    defer for(list.items) |i| alloc.free(i);
+
+    while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
+        var linec = try alloc.alloc(u8, 256);
+
+        @memset(linec, 0);
+        @memcpy(linec[0..line.len], line);
+        try list.append(linec);
+    }
+
+    var count: u64 = 0;
+
+    var y: isize = 0;
+    while(y < list.items.len) : (y += 1) {
+        var x: usize = 0;
+        while(x < list.items[0].len) : (x += 1){
+            if(list.items[@intCast(y)][x] == '@' and adj(list, x, @intCast(y)) < 4) {
+                list.items[@intCast(y)][x] = '.';
+                if(y != 0) y -= 1;
+                y -= 1;
+                count += 1;
+                break;
+            }
+        }
+    }
+
+    std.debug.print("{d}\n", .{count});
+}