diff --git a/src/days.rs b/src/days.rs
index 7f0258a..1c4b09e 100644
--- a/src/days.rs
+++ b/src/days.rs
@@ -8,7 +8,7 @@ pub mod d7;
 pub mod d8;
 pub mod d9;
 pub mod d10;
-// pub mod d11;
+pub mod d11;
 // pub mod d12;
 // pub mod d13;
 // pub mod d14;
diff --git a/src/days/d11.rs b/src/days/d11.rs
new file mode 100644
index 0000000..5920a89
--- /dev/null
+++ b/src/days/d11.rs
@@ -0,0 +1,71 @@
+use crate::prelude::*;
+
+pub type I = Vec<Vec<char>>;
+pub type O = i64;
+
+fn _parse (data: &str) -> I {
+    Default::default()
+}
+
+fn _solve (data: &I) -> O {
+    Default::default()
+}
+
+fn _silver (data: &I) -> O {
+
+
+    Default::default()
+}
+
+fn _gold (data: &I) -> O {
+    Default::default()
+}
+
+type St = [Vec<char>; 4];
+
+fn is_final_state (state: &St) -> bool {
+    state[1..].iter().all(|e| e.is_empty())
+}
+
+fn is_valid_state (state: &St) -> bool {
+    state.iter().all(|level| level.len() < 2 || level.iter().all(|e| e.is_lowercase()) || {
+        let mut chips = level.iter().filter(|e| e.is_uppercase());
+        while let Some(chip) = chips.next() {
+            if level.iter().find(|&v| chip.to_ascii_lowercase() == *v).is_none() {
+                return false;
+            }
+        }
+        true
+    })
+}
+
+fn state_discriminant (state: &St) -> [(usize, usize); 4] {
+    state.iter().map(|s| (
+        s.iter().filter(|e| e.is_lowercase()).count(),
+        s.iter().filter(|e| e.is_uppercase()).count()
+    )).collect_vec().try_into().unwrap()
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    fn read () -> I {
+        vec![vec!['a', 'b', 'c', 'd', 'e', 'A', 'B', 'C'], vec!['D', 'E'], vec![], vec![]]
+    }
+
+    #[test]
+    fn silver () {
+        let data = read();
+        let ans = _silver(&data);
+
+        assert_eq!(ans, 1)
+    }
+
+    #[test]
+    fn gold () {
+        let data = read();
+        let ans = _gold(&data);
+
+        assert_eq!(ans, 1)
+    }
+}