1 files changed, 98 insertions, 0 deletions
diff --git a/2016/aoc1/src/main.rs b/2016/aoc1/src/main.rs
new file mode 100644
index 0000000..e9b4138
--- /dev/null
+++ b/2016/aoc1/src/main.rs
@@ -0,0 +1,98 @@
+use std::io::Read;
+use std::fs::File;
+
+#[derive(Clone, Copy, Debug)]
+enum Direction {
+    Up,
+    Left,
+    Down,
+    Right
+}
+
+impl Direction {
+    fn turn_right(self) -> Direction {
+        match self {
+            Direction::Up => Direction::Right,
+            Direction::Right => Direction::Down,
+            Direction::Down => Direction::Left,
+            Direction::Left => Direction::Up
+        }
+    }
+    fn turn_left(self) -> Direction {
+        //not an ambiturner
+        self.turn_right().turn_right().turn_right()
+    }
+
+    fn as_vector(self, dist: i32) -> (i32,i32) {
+        match self {
+            Direction::Up => (0, -dist),
+            Direction::Right => (dist, 0),
+            Direction::Down => (0, dist),
+            Direction::Left => (-dist, 0)
+        }
+    }
+}
+
+fn main() {
+    let content = read_file().expect("Failed to read file");
+    let (_, dist_x, dist_y) = first_repeated_dest(content);
+    println!("Total: ({}, {})", dist_x, dist_y);
+    println!("Net: {}", dist_x+dist_y);
+}
+
+fn net_distance(content: String) -> (Direction, i32, i32) {
+    content.trim().split(", ")
+        .map(|action|
+             (
+                 action.chars().nth(0).unwrap(),
+                 action.chars().skip(1).collect::<String>().parse::<i32>().unwrap()
+             ))
+        .fold((Direction::Up, 0,0), |(facing, acc_x, acc_y), (dir, dist)| {
+            let new_facing = match dir {
+                'R' => facing.turn_right(),
+                'L' => facing.turn_left(),
+                _ => panic!("bad input")
+            };
+              
+            let (new_x, new_y) = new_facing.as_vector(dist);
+            (new_facing, acc_x+new_x, acc_y+new_y)
+        })
+}
+
+fn first_repeated_dest(content: String) -> (Direction, i32, i32) {
+    let mut stops: Vec<(i32, i32)> = Vec::new();
+    let actions = content.trim().split(", ")
+        .map(|action|
+             (
+                 action.chars().nth(0).unwrap(),
+                 action.chars().skip(1).collect::<String>().parse::<i32>().unwrap()
+             ));
+    let mut current_facing = Direction::Up;
+    let (mut acc_x, mut acc_y) = (0, 0);
+    for (dir, dist) in actions {
+        current_facing = match dir {
+                'R' => current_facing.turn_right(),
+                'L' => current_facing.turn_left(),
+                _ => panic!("bad input")
+            };
+
+        for _ in 0..dist {
+            let (new_x, new_y) = current_facing.as_vector(1);
+            acc_x += new_x;
+            acc_y += new_y;
+
+            if stops.iter().any(|&(x, y)| x==acc_x && y==acc_y) {
+                return (current_facing, acc_x, acc_y);
+            }
+            stops.push((acc_x, acc_y));
+        }
+    }
+    (current_facing, acc_x, acc_y)
+}
+
+fn read_file() -> Result<String, String> {
+    let mut file = try!(File::open("input.txt").map_err(|e| e.to_string()));
+    let mut content = String::new();
+    try!(file.read_to_string(&mut content).map_err(|e| e.to_string()));
+    Ok(content)
+}