2020 day 20-22

2020/d21.py

@@ -0,0 +1,50 @@
+from collections import defaultdict
+from lib import get_data
+
+data = get_data(__file__)
+
+algs_to_ings = defaultdict(set)
+ings_counts = defaultdict(int)
+
+for line in data.splitlines():
+    a, b = line.split(" (contains ")
+    ings = a.split(" ")
+    algs = b[:-1].split(", ")
+    for ing in ings:
+        ings_counts[ing] += 1
+
+    for a in algs:
+        if a not in algs_to_ings:
+            algs_to_ings[a] = set(ings)
+        else:
+            algs_to_ings[a] &= set(ings)
+
+
+for ings in algs_to_ings.values():
+    for ing in ings:
+        if ing in ings_counts:
+            del ings_counts[ing]
+t = sum(ings_counts.values())
+print(t)
+
+
+algs_to_ings = {a: list(ing) for a, ing in algs_to_ings.items()}
+
+handled = set()
+while True:
+    to_remove = None
+    for alg, ings in algs_to_ings.items():
+        if len(ings) == 1 and ings[0] not in handled:
+            to_remove = ings[0]
+            break
+    else:
+        break
+    assert to_remove is not None
+    handled.add(to_remove)
+    for ings in algs_to_ings.values():
+        if len(ings) > 1 and to_remove in ings:
+            ings.remove(to_remove)
+
+xs = sorted([(a, i[0]) for a, i in algs_to_ings.items()])
+xs = ",".join([x[1] for x in xs])
+print(xs)