From 8e2ac7c1e6ea2653bf3afb68c367f5b78396c181 Mon Sep 17 00:00:00 2001
From: Tomasz Kramkowski <tk@the-tk.com>
Date: Wed, 8 Dec 2021 09:04:04 +0000
Subject: day 8

---
 8.py | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 8.py

diff --git a/8.py b/8.py
new file mode 100644
index 0000000..0bd67ed
--- /dev/null
+++ b/8.py
@@ -0,0 +1,71 @@
+from collections import Counter
+from itertools import chain
+from utils import open_day
+from enum import IntEnum, auto
+
+fset = frozenset
+
+class Seg(IntEnum):
+    A = 0
+    B = auto()
+    C = auto()
+    D = auto()
+    E = auto()
+    F = auto()
+    G = auto()
+
+dig = [
+    fset((Seg.A, Seg.B, Seg.C, Seg.E, Seg.F, Seg.G)),
+    fset((Seg.C, Seg.F)),
+    fset((Seg.A, Seg.C, Seg.D, Seg.E, Seg.G)),
+    fset((Seg.A, Seg.C, Seg.D, Seg.F, Seg.G)),
+    fset((Seg.B, Seg.C, Seg.D, Seg.F)),
+    fset((Seg.A, Seg.B, Seg.D, Seg.F, Seg.G)),
+    fset((Seg.A, Seg.B, Seg.D, Seg.E, Seg.F, Seg.G)),
+    fset((Seg.A, Seg.C, Seg.F)),
+    fset((Seg.A, Seg.B, Seg.C, Seg.D, Seg.E, Seg.F, Seg.G)),
+    fset((Seg.A, Seg.B, Seg.C, Seg.D, Seg.F, Seg.G)),
+]
+
+seg = [
+    fset((0, 2, 3, 5, 6, 7, 8, 9)),
+    fset((0, 4, 5, 6, 8, 9)),
+    fset((0, 1, 2, 3, 4, 7, 8, 9)),
+    fset((2, 3, 4, 5, 6, 8, 9)),
+    fset((0, 2, 6, 8)),
+    fset((0, 1, 3, 4, 5, 6, 7, 8, 9)),
+    fset((0, 2, 3, 5, 6, 8, 9)),
+]
+
+counts = Counter()
+count = 0
+with open_day(8) as f:
+    for line in f:
+        patterns, digits = line.rstrip().split(' | ')
+        patterns = fset(fset(p) for p in patterns.split())
+        countmap = {
+            count: seg
+            for seg, count in Counter(chain.from_iterable(patterns)).items()
+        }
+        def patbylen(l): return next(p for p in patterns if len(p) == l)
+        CF      = patbylen(len(dig[1]))
+        BCDF    = patbylen(len(dig[4]))
+        ACF     = patbylen(len(dig[7]))
+        ABCDEFG = patbylen(len(dig[8]))
+        segmap = dict()
+        segmap[Seg.B] = countmap[len(seg[Seg.B])]
+        segmap[Seg.E] = countmap[len(seg[Seg.E])]
+        segmap[Seg.F] = countmap[len(seg[Seg.F])]
+        def single(s):
+            assert(len(s) == 1)
+            return next(iter(s))
+        segmap[Seg.A] = single(ACF - CF)
+        segmap[Seg.C] = single(CF - fset(segmap[Seg.F]))
+        segmap[Seg.D] = single(BCDF - CF - fset(segmap[Seg.B]))
+        segmap[Seg.G] = single(ABCDEFG - fset(segmap.values()))
+        digmap = { fset(segmap[s] for s in dig[i]): i for i in range(10) }
+        digits = [digmap[fset(d)] for d in digits.split()]
+        counts.update(digits)
+        count += sum(d * 10 ** i for i, d in enumerate(reversed(digits)))
+print(counts[1] + counts[4] + counts[7] + counts[8])
+print(count)
-- 
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