diff --git a/13/input b/13/input
new file mode 100644
index 0000000..5b61af0
--- /dev/null
+++ b/13/input
@@ -0,0 +1,876 @@
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+
+fold along x=655
+fold along y=447
+fold along x=327
+fold along y=223
+fold along x=163
+fold along y=111
+fold along x=81
+fold along y=55
+fold along x=40
+fold along y=27
+fold along y=13
+fold along y=6
diff --git a/13/solve.zig b/13/solve.zig
new file mode 100644
index 0000000..914b4ac
--- /dev/null
+++ b/13/solve.zig
@@ -0,0 +1,85 @@
+const std = @import("std");
+const print = std.debug.print;
+
+const Point = [2]u32;
+// const Point = struct {
+//     x: u32,
+//     y: u32,
+// };
+
+pub fn main() !void {
+    var alloc = std.heap.GeneralPurposeAllocator(.{}){};
+    defer std.debug.assert(!alloc.deinit());
+    var gpa = &alloc.allocator;
+
+    const stdin = std.io.getStdIn().reader();
+
+    var res: usize = 0;
+    var res2: u32 = 0;
+
+    var points = std.ArrayList(Point).init(gpa);
+    defer points.deinit();
+
+    var tmp: [256]u8 = undefined;
+    // read points
+    while (try stdin.readUntilDelimiterOrEof(&tmp, '\n')) |line| {
+        if (line.len == 0) {
+            break;
+        }
+        var it = std.mem.split(line, ",");
+        var x = try std.fmt.parseInt(u32, it.next() orelse unreachable, 10);
+        var y = try std.fmt.parseInt(u32, it.next() orelse unreachable, 10);
+        try points.append(Point{x, y});
+    }
+    // read folds
+    while (try stdin.readUntilDelimiterOrEof(&tmp, '\n')) |line| {
+        const idx: u1 = if (line[11] == 'x') 0 else 1;
+        const place = try std.fmt.parseInt(u32, line[13..], 10);
+
+        var remove = std.ArrayList(usize).init(gpa);
+        defer remove.deinit();
+
+        for (points.items) |_, i| {
+            var point = points.items[i];
+            if (point[idx] > place) {
+                point[idx] = place - (point[idx] - place);
+                points.items[i] = point;
+                for (points.items) |other, j| {
+                    if (point[0] == other[0] and point[1] == other[1] and i != j) {
+                        try remove.append(i);
+                    }
+                }
+            }
+        }
+
+        std.mem.reverse(usize, remove.items);
+        for (remove.items) |i| {
+            _ = points.swapRemove(i);
+        }
+
+        if (res == 0) res = points.items.len;
+    }
+
+    print("{}\n", .{res});
+    var maxX: u32 = 0;
+    var maxY: u32 = 0;
+    for (points.items) |point| {
+        maxX = std.math.max(maxX, point[0]);
+        maxY = std.math.max(maxY, point[1]);
+    }
+
+    var y: u32 = 0;
+    while (y <= maxY) : (y += 1) {
+        var x: u32 = 0;
+        while (x <= maxX) : (x += 1) {
+            var char: [1]u8 = [1]u8{'.'};
+            for (points.items) |point| {
+                if (point[0] == x and point[1] == y) {
+                    char[0] = '#';
+                }
+            }
+            print("{s}", .{char});
+        }
+        print("\n", .{});
+    }
+}
diff --git a/13/testinput b/13/testinput
new file mode 100644
index 0000000..32a8563
--- /dev/null
+++ b/13/testinput
@@ -0,0 +1,21 @@
+6,10
+0,14
+9,10
+0,3
+10,4
+4,11
+6,0
+6,12
+4,1
+0,13
+10,12
+3,4
+3,0
+8,4
+1,10
+2,14
+8,10
+9,0
+
+fold along y=7
+fold along x=5
\ No newline at end of file