1 files changed, 156 insertions, 0 deletions
diff --git a/2016/src/bin/day02.rs b/2016/src/bin/day02.rs
new file mode 100644
index 0000000..f7cc624
--- /dev/null
+++ b/2016/src/bin/day02.rs
@@ -0,0 +1,156 @@
+use std::io::{self, Read};
+
+trait Pad: Copy + Default {
+    fn up(self) -> Self;
+    fn down(self) -> Self;
+    fn left(self) -> Self;
+    fn right(self) -> Self;
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Keypad {
+    K1, K2, K3,
+    K4, K5, K6,
+    K7, K8, K9,
+}
+
+impl Default for Keypad {
+    fn default() -> Self { Keypad::K5 }
+}
+
+impl Pad for Keypad {
+    fn up(self) -> Self {
+        use Keypad::*;
+        match self {
+            K4 => K1, K5 => K2, K6 => K3,
+            K7 => K4, K8 => K5, K9 => K6,
+            _ => self,
+        }
+    }
+
+    fn down(self) -> Self {
+        use Keypad::*;
+        match self {
+            K1 => K4, K2 => K5, K3 => K6,
+            K4 => K7, K5 => K8, K6 => K9,
+            _ => self,
+        }
+    }
+
+    fn left(self) -> Self {
+        use Keypad::*;
+        match self {
+            K2 => K1, K3 => K2,
+            K5 => K4, K6 => K5,
+            K8 => K7, K9 => K8,
+            _ => self,
+        }
+    }
+
+    fn right(self) -> Self {
+        use Keypad::*;
+        match self {
+            K1 => K2, K2 => K3,
+            K4 => K5, K5 => K6,
+            K7 => K8, K8 => K9,
+            _ => self,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Wackypad {
+            K1,
+        K2, K3, K4,
+    K5, K6, K7, K8, K9,
+        KA, KB, KC,
+            KD,
+}
+
+impl Default for Wackypad {
+    fn default() -> Self { Wackypad::K5 }
+}
+
+impl Pad for Wackypad {
+    fn up(self) -> Self {
+        use Wackypad::*;
+        match self {
+                      K3 => K1,
+            K6 => K2, K7 => K3, K8 => K4,
+            KA => K6, KB => K7, KC => K8,
+                      KD => KB,
+            _ => self,
+        }
+    }
+
+    fn down(self) -> Self {
+        use Wackypad::*;
+        match self {
+                      K1 => K3,
+            K2 => K6, K3 => K7, K4 => K8,
+            K6 => KA, K7 => KB, K8 => KC,
+                      KB => KD,
+            _ => self,
+        }
+    }
+
+    fn left(self) -> Self {
+        use Wackypad::*;
+        match self {
+                      K3 => K2, K4 => K3,
+            K6 => K5, K7 => K6, K8 => K7, K9 => K8,
+                      KB => KA, KC => KB,
+            _ => self,
+        }
+    }
+
+    fn right(self) -> Self {
+        use Wackypad::*;
+        match self {
+                      K2 => K3, K3 => K4,
+            K5 => K6, K6 => K7, K7 => K8, K8 => K9,
+                      KA => KB, KB => KC,
+            _ => self,
+        }
+    }
+}
+
+fn solve<P: Pad>(input: &str) -> Vec<P> {
+    let mut code = Vec::new();
+    let mut key = P::default();
+
+    for line in input.lines() {
+        for direction in line.chars() {
+            key = match direction {
+                'U' => key.up(),
+                'D' => key.down(),
+                'L' => key.left(),
+                'R' => key.right(),
+                _ => panic!("{} is not a direction", direction),
+            }
+        }
+        code.push(key);
+    }
+
+    code
+}
+
+fn main() {
+    let mut input = String::new();
+    io::stdin().read_to_string(&mut input).unwrap();
+
+    println!("Part 1: {:?}", solve::<Keypad>(&input));
+    println!("Part 2: {:?}", solve::<Wackypad>(&input));
+}
+
+#[test]
+fn part1() {
+    use Keypad::*;
+    assert_eq!(vec![K1, K9, K8, K5], solve("ULL\nRRDDD\nLURDL\nUUUUD"));
+}
+
+#[test]
+fn part2() {
+    use Wackypad::*;
+    assert_eq!(vec![K5, KD, KB, K3], solve("ULL\nRRDDD\nLURDL\nUUUUD"));
+}