[Python/2016] Move solutions into .py files

Python/2016/17.py

@@ -0,0 +1,68 @@
+from lib import *
+
+input = read_input(2016, 17).strip()
+
+
+def get_state(path):
+    digest = hashlib.md5((input + path).encode()).hexdigest()
+    return [c >= "b" for c in digest[:4]]  # up, down, left, right
+
+
+def find_path():
+    queue = [("", 0, 0)]
+    while True:
+        path, x, y = queue.pop(0)
+
+        if x == y == 3:
+            return path
+
+        up, down, left, right = get_state(path)
+
+        if up and y > 0:
+            queue.append((path + "U", x, y - 1))
+
+        if down and y < 3:
+            queue.append((path + "D", x, y + 1))
+
+        if left and x > 0:
+            queue.append((path + "L", x - 1, y))
+
+        if right and x < 3:
+            queue.append((path + "R", x + 1, y))
+
+
+print(find_path())
+
+
+def find_path():
+    queue = [("", 0, 0)]
+
+    longest = ""
+
+    while queue:
+        path, x, y = queue.pop(0)
+
+        if x == y == 3:
+            if len(path) > len(longest):
+                longest = path
+
+            continue
+
+        up, down, left, right = get_state(path)
+
+        if up and y > 0:
+            queue.append((path + "U", x, y - 1))
+
+        if down and y < 3:
+            queue.append((path + "D", x, y + 1))
+
+        if left and x > 0:
+            queue.append((path + "L", x - 1, y))
+
+        if right and x < 3:
+            queue.append((path + "R", x + 1, y))
+
+    return longest
+
+
+print(len(find_path()))