🍷

makefile

@@ -9,7 +9,7 @@ main: venv/
 
 venv/: requirements.txt
 	rm -rf venv/
-	python3 -m venv venv
+	~/.pyenv/versions/3.8.0/bin/python -m venv venv
 	venv/bin/pip install -r requirements.txt
 	touch requirements.txt venv/
 	# install flake8 git hook

y2019/p23.py

@@ -0,0 +1,46 @@
+import collections
+import sys
+import threading
+
+from intcode import compute
+
+
+def communicate(n):
+    yield n
+    while True:
+        while queues[n]:
+            yield queues[n].popleft()
+        yield -1
+
+
+def handle(n):
+    bot = compute(text, communicate(n))
+    for addr, X, Y in zip(bot, bot, bot):
+        if addr == 255:
+            NAT.append((X, Y))
+        else:
+            queues[addr].extend((X, Y))
+
+
+text = sys.stdin.read()
+
+queues = collections.defaultdict(collections.deque)
+NAT = []
+for n in range(50):
+    threading.Thread(target=handle, args=[n], daemon=True).start()
+
+seen = set()
+while True:
+    activity = sum(len(q) for q in queues.values())
+    if not activity and len(NAT):
+        X, Y = NAT[-1]
+
+        if len(NAT) == 1:
+            print(Y)
+
+        if Y in seen:
+            print(Y)
+            break
+
+        queues[0] += [X, Y]
+        seen.add(Y)