Day 11: Hex distances

1 files changed, 57 insertions, 0 deletions

diff --git a/src/bin/day_11.rs b/src/bin/day_11.rs
new file mode 100644
index 0000000..ffb0833
--- /dev/null
+++ b/src/bin/day_11.rs
@@ -0,0 +1,57 @@
+extern crate advent_of_code_2017;
+use advent_of_code_2017::*;
+
+fn main() {
+    let args = AdventArgs::init();
+
+    let directions: Vec<&str> = args.input[0].split(",").collect();
+
+    let mut x = 0.0;
+    let mut y = 0.0;
+    
+    let mut max_away = 0.0;
+    
+    for dir in directions {
+        y += match dir {
+            "ne" => 0.5,
+            "n" => 1.0,
+            "nw" => 0.5,
+            "se" => -0.5,
+            "s" => -1.0,
+            "sw" => -0.5,
+            _ => panic!("Unexpected direction {}", dir)
+        };
+
+        x += match dir {
+            "ne" => -0.5,
+            "n" => 0.0,
+            "nw" => 0.5,
+            "se" => -0.5,
+            "s" => 0.0,
+            "sw" => 0.5,
+            _ => panic!("Unexpected direction {}", dir)
+        };
+
+        let current_distance = tile_distance(x, y);
+        if current_distance > max_away {
+            max_away = current_distance;
+        }
+    }
+
+    if args.part == 1 {
+        println!("Child process is {} away", tile_distance(x, y));
+    } else {
+        println!("At most, child process was {} away", max_away);
+    }
+    
+}
+
+fn tile_distance(x: f32, y: f32) -> f32 {
+    let tiles_x = x.abs()*2.0;
+    let tiles_y = if y.abs() < tiles_x {
+        0.0
+    } else {
+        y.abs() - tiles_x
+    };
+    tiles_x + tiles_y
+}