1 files changed, 52 insertions, 0 deletions
diff --git a/2017/src/bin/day_14.rs b/2017/src/bin/day_14.rs
new file mode 100644
index 0000000..778a57f
--- /dev/null
+++ b/2017/src/bin/day_14.rs
@@ -0,0 +1,52 @@
+extern crate advent_of_code_2017;
+use advent_of_code_2017::*;
+
+fn main() {
+    let args = AdventArgs::init();
+    let input = args.input[0].clone();
+
+    let mut used = 0;
+    let mut grid: Vec<Vec<bool>> = vec!(vec!(false; 128); 128);
+    for i in 0..128 {
+        let to_hash = format!("{}-{}", input, i);
+        let hash = knot_hash(&to_hash);
+        for (x1,c) in hash.chars().enumerate() {
+            let parsed = u32::from_str_radix(&c.to_string(), 16).unwrap();
+            used += parsed.count_ones();
+            for (x2,b) in format!("{:04b}",parsed).chars().enumerate() {
+                grid[i][4*x1+x2] = b == '1';
+            }
+        }
+    }
+
+    if args.part == 1 {
+        println!("{} is used", used);
+    } else {
+        let mut group_count = 0;
+        for start_y in 0..128 {
+            for start_x in 0..128 {
+                if grid[start_y][start_x] {
+                    group_count += 1;
+                    clear_group(&mut grid, Point{
+                        x: start_x as i32,
+                        y: start_y as i32
+                    });
+                }
+            }
+        }
+        println!("{} groups", group_count);
+        
+    }
+}
+
+fn clear_group(grid: &mut Vec<Vec<bool>>, point: Point) {
+    if point.x >= 0 && point.x < 128 && point.y >= 0 && point.y < 128 {
+        if grid[point.y as usize][point.x as usize] {
+            grid[point.y as usize][point.x as usize] = false;
+            clear_group(grid, point.up());
+            clear_group(grid, point.down());
+            clear_group(grid, point.left());
+            clear_group(grid, point.right());
+        }
+    }
+}