1 files changed, 29 insertions, 0 deletions
diff --git a/2015/rs/src/three.rs b/2015/rs/src/three.rs
new file mode 100644
index 0000000..04db03a
--- /dev/null
+++ b/2015/rs/src/three.rs
@@ -0,0 +1,29 @@
+use std::collections::HashSet;
+
+static INPUT: &'static str = include_str!("three.txt");
+
+fn main() {
+  let valueified = INPUT.chars().map(|c| match c { '<' => (-1, 0), '>' => (1, 0), '^' => (0, 1), 'v' => (0, -1), _ => (0, 0) });
+
+  let mut visited = HashSet::new();
+  append_visits(valueified.clone(), &mut visited);
+  println!("Number visited normally: {}", visited.len());
+
+  let santa_iter = valueified.clone().step_by(2);
+  let robot_iter = valueified.skip(1).step_by(2);
+
+  let mut visited = HashSet::new();
+  append_visits(santa_iter.clone(), &mut visited);
+  append_visits(robot_iter.clone(), &mut visited);
+  println!("Number visited w/ robot: {}", visited.len());
+}
+
+fn append_visits<I: Iterator<Item = (i32, i32)>>(iter: I, visited: &mut HashSet<(i32, i32)>) {
+  let (mut x, mut y) = (0, 0);
+  visited.insert((0, 0));
+  for (move_x, move_y) in iter {
+    x += move_x;
+    y += move_y;
+    visited.insert((x, y));
+  }
+}