lint

2020/day16.py

@@ -1,7 +1,5 @@
 import sys
-from collections import defaultdict
 from functools import reduce
-from itertools import permutations
 
 
 def main():

2020/day21.py

@@ -0,0 +1,43 @@
+import re
+import sys
+from functools import reduce
+
+LINE_RE = re.compile(r"(.+) \(contains (.+)\)")
+
+def main():
+    lines = [line.rstrip() for line in sys.stdin]
+    foods = []
+    for line in lines:
+        i, a = LINE_RE.match(line).groups()
+        foods.append((set(i.split()), set(a.split(", "))))
+    ingredients = set(i for il, _ in foods for i in il)
+    allergens = set(a for _, al in foods for a in al)
+
+    # Part 1
+    matches = {}
+    while len(matches) < len(allergens):
+        for allergen in allergens:
+            p_ings = [
+                set(filter(lambda i: i not in matches, f[0]))
+                for f in foods if allergen in f[1]
+            ]
+            c_ings = reduce(lambda a, b: a & b, p_ings, ingredients)
+            if len(c_ings) == 1:
+                i = c_ings.pop()
+                matches[i] = allergen
+    clean_ings = ingredients.difference(set(matches.keys()))
+    num_appearances = sum(
+        ci in fis
+        for fis, _ in foods
+        for ci in clean_ings
+    )
+    print(f"Clean ingredients appear {num_appearances} times.")
+
+    # Part 2
+    canonical = ",".join(
+        f for f, a in sorted(matches.items(), key=lambda m: m[1])
+    )
+    print("Canonical list:", canonical)
+
+if __name__ == "__main__":
+    main()

2020/day22.py

@@ -0,0 +1,57 @@
+import sys
+
+def main():
+    lines = [line.rstrip() for line in sys.stdin]
+    deck1, deck2 = parse_lines(lines)
+
+    # Part 1
+    while deck1 and deck2:
+        c1, c2 = deck1.pop(0), deck2.pop(0)
+        if c1 > c2:
+            deck1 += [c1, c2]
+        else:
+            deck2 += [c2, c1]
+    deck_win = deck1 or deck2
+    print("Score:", score(deck_win))
+
+    # Part 2
+    deck1, deck2 = parse_lines(lines)
+    winner = rec_game(deck1, deck2)
+    deck_win = deck1 if winner == 1 else deck2
+    print("Score:", score(deck_win))
+
+def parse_lines(lines):
+    deck1, deck2 = [], []
+    for line in lines:
+        if not line:
+            continue
+        if line.startswith("P"):
+            deck = deck1 if int(line[7:8]) == 1 else deck2
+        else:
+            deck.append(int(line))
+    return deck1, deck2
+
+def score(deck):
+    return sum(c * (i + 1) for i, c in enumerate(reversed(deck)))
+
+def rec_game(deck1, deck2):
+    past_decks = set()
+    while deck1 and deck2:
+        h = tuple(deck1), tuple(deck2)
+        if h in past_decks:
+            return 1
+        past_decks.add(h)
+        c1, c2 = deck1.pop(0), deck2.pop(0)
+        if len(deck1) >= c1 and len(deck2) >= c2:
+            if rec_game(deck1[:c1], deck2[:c2]) == 1:
+                deck1 += [c1, c2]
+            else:
+                deck2 += [c2, c1]
+        elif c1 > c2:
+            deck1 += [c1, c2]
+        else:
+            deck2 += [c2, c1]
+    return 1 if deck1 else 2
+
+if __name__ == "__main__":
+    main()

2020/new.py

@@ -6,11 +6,9 @@ from datetime import date
 TEMPLATE = """\
 import sys
 
-
 def main():
     lines = [line.rstrip() for line in sys.stdin]
 
-
 if __name__ == "__main__":
     main()
 """