Solve 2021 day 7-11

2021/d8.py

@@ -0,0 +1,65 @@
+from lib import get_data
+from itertools import permutations
+
+data = get_data(__file__).strip()
+
+code_to_num = {
+    "cf": 1,
+    "acf": 7,
+    "bcdf": 4,
+    "acdeg": 2,
+    "acdfg": 3,
+    "abdfg": 5,
+    "abcefg": 0,
+    "abdefg": 6,
+    "abcdfg": 9,
+    "abcdefg": 8,
+}
+
+
+def translate(inn, mapping):
+    out = ""
+    for c in inn:
+        out += mapping[c]
+    return "".join(sorted(out))
+
+
+def decode(inn, out):
+    s = "abcdefg"
+    m = None
+    for p in permutations(s):
+        m = {k: v for k, v in zip(p, s)}
+        all = set(code_to_num.keys())
+        for in_code in inn:
+            out_code = translate(in_code, m)
+            if out_code in all:
+                all.remove(out_code)
+
+        if len(all) == 0:
+            break
+        else:
+            m = None
+
+    assert m is not None
+
+    o = 0
+    d = 1000
+    for out_code in out:
+        out_code = translate(out_code, m)
+        v = code_to_num[out_code]
+        o += d * v
+        d //= 10
+    return o
+
+
+s1 = 0
+s2 = 0
+for line in data.splitlines():
+    inn, out = line.strip().split(" | ")
+    inn = inn.split()
+    out = out.split()
+    s1 += sum(1 for v in out if len(v) in [2, 3, 4, 7])
+    s2 += decode(inn, out)
+
+print(s1)
+print(s2)