From 3873358c14ca92b3ded56c5ef34d2a874310bd14 Mon Sep 17 00:00:00 2001
From: Gabriel Augendre <gabriel@augendre.info>
Date: Fri, 9 Dec 2022 10:29:28 +0100
Subject: [PATCH] Solve day9 part 2

---
 2022/day09_bridge.py    | 34 +++++++++++++++++++++++++++++++---
 2022/inputs/day09-test2 |  8 ++++++++
 2 files changed, 39 insertions(+), 3 deletions(-)
 create mode 100644 2022/inputs/day09-test2

diff --git a/2022/day09_bridge.py b/2022/day09_bridge.py
index a7ca75f..d5c168c 100644
--- a/2022/day09_bridge.py
+++ b/2022/day09_bridge.py
@@ -87,9 +87,37 @@ def solve_part_1(instructions: DataType) -> int:
 
 
 def solve_part_2(instructions: DataType) -> int:
-    return 0
+    head = Point()
+    tails = [Point() for _ in range(9)]
+    visited = set()
+    for instruction in instructions:
+        print(instruction)
+        count = instruction[1]
+        while count > 0:
+            head.move(instruction)
+            tails[0].follow(head)
+            for i in range(1, len(tails)):
+                tails[i].follow(tails[i - 1])
+            tail_tuple = tails[-1].tuple
+            visited.add(tail_tuple)
+            count -= 1
+        # print_grid([head, *tails])
+    return len(visited)
+
+
+def print_grid(rope: list[Point], size: tuple[int, int] = (21, 27)) -> None:
+    rope = [knot.tuple for knot in rope]
+    for row in range(int(-size[0] / 2), int(size[0] / 2)):
+        for col in range(int(-size[1] / 2), int(size[1] / 2)):
+            try:
+                char = rope.index((col, row))
+            except ValueError:
+                char = "."
+            print(char, end="")
+        print()
 
 
 if __name__ == "__main__":
-    main("inputs/day09-test1", expected_part_1=13)
-    main("inputs/day09", expected_part_1=5619)
+    main("inputs/day09-test1", expected_part_1=13, expected_part_2=1)
+    main("inputs/day09-test2", expected_part_2=36)
+    main("inputs/day09", expected_part_1=5619, expected_part_2=2376)
diff --git a/2022/inputs/day09-test2 b/2022/inputs/day09-test2
new file mode 100644
index 0000000..60bd43b
--- /dev/null
+++ b/2022/inputs/day09-test2
@@ -0,0 +1,8 @@
+R 5
+U 8
+L 8
+D 3
+R 17
+D 10
+L 25
+U 20