🐤

y2019/intcode.py

@@ -1,3 +1,4 @@
+import itertools
 import re
 
 
@@ -19,9 +20,11 @@ def get_parameters(ns, pos, modes, N, writes):
     yield pos + N
 
 
-def compute(ns, inp):
+def compute(ns, in_iter):
     if isinstance(ns, str):
         ns = parse(ns)
+    if isinstance(in_iter, int):
+        in_iter = itertools.cycle([in_iter])
 
     pos = 0
     consume = lambda n, writes='': get_parameters(ns, pos, modes, n, writes)
@@ -43,7 +46,7 @@ def compute(ns, inp):
 
         elif op == 3:
             a, pos = consume(1, 'a')
-            ns[a] = inp
+            ns[a] = next(in_iter)
 
         elif op == 4:
             a, pos = consume(1)

y2019/p07.py

@@ -0,0 +1,35 @@
+import sys
+import itertools
+from intcode import compute
+
+
+ns = sys.stdin.read()
+
+
+def solve(ns, phases):
+    out = 0
+    for n in phases:
+        out = list(compute(ns, iter([n, out])))[-1]
+    return out
+
+print(max(solve(ns, phases) for phases in itertools.permutations(range(5))))
+
+
+def solve2(ns, phases):
+    feedback = []
+    iter_phases = iter(phases)
+    iter_feed = iter(feedback)
+    loop = itertools.cycle([
+        compute(ns, itertools.chain([next(iter_phases), 0], iter_feed)),
+        compute(ns, itertools.chain([next(iter_phases)], iter_feed)),
+        compute(ns, itertools.chain([next(iter_phases)], iter_feed)),
+        compute(ns, itertools.chain([next(iter_phases)], iter_feed)),
+        compute(ns, itertools.chain([next(iter_phases)], iter_feed)),
+    ])
+    try:
+        for machine in loop:
+            feedback.append(next(machine))
+    except StopIteration:
+        return feedback[-1]
+
+print(max(solve2(ns, phases) for phases in itertools.permutations(range(5, 10))))