2020/14

y2020/p14.py

+import re
+import sys
+from itertools import product
+
+
+text = sys.stdin.read()
+
+
+mem = {}
+idem = {'0': '0', '1': '1'}
+for line in text.splitlines():
+    typ, val = line.split(' = ')
+    if typ.startswith('mask'):
+        mask = val
+    if typ.startswith('mem'):
+        pos = int(typ[4:-1])
+        known = f'{int(val):b}'.zfill(len(mask))
+        string = ''.join(idem.get(c, known[i]) for i, c in enumerate(mask))
+        mem[pos] = int(string, 2)
+print(sum(mem.values()))
+
+
+mem = {}
+idem = {'X': 'X', '1': '1'}
+for line in text.splitlines():
+    typ, val = line.split(' = ')
+    if typ.startswith('mask'):
+        mask = val
+    elif typ.startswith('mem'):
+        known = f'{int(typ[4:-1]):b}'.zfill(len(mask))
+        string = ''.join(idem.get(c, known[i]) for i, c in enumerate(mask))
+        for gen in map(iter, product('01', repeat=string.count('X'))):
+            tmp = re.sub('X', lambda m: next(gen), string)
+            pos = int(tmp, 2)
+            mem[pos] = int(val)
+print(sum(mem.values()))