2020/16

toolkit.py

@@ -10,6 +10,10 @@ from pathlib import Path
 import requests
 
 
+def integers(line):
+    return [int(n) for n in re.findall(r'\d+', line)]
+
+
 def lcm(a, b):
     return abs(a * b) // math.gcd(a, b)
 

y2020/p16.py

@@ -0,0 +1,35 @@
+import sys
+
+import toolkit
+
+
+def parse_info(info):
+    out = {}
+    for line in info.splitlines():
+        key, vals = line.split(':')
+        out[key] = set()
+        for a, b in zip(*[iter(toolkit.integers(vals))] * 2):
+            out[key] |= set(range(a, b + 1))
+    return out
+
+
+text = sys.stdin.read()
+info, mine, rest = text.split('\n\n')
+info = parse_info(info).items()
+mine = toolkit.integers(mine)
+
+rest = [toolkit.integers(ln) for ln in rest.splitlines()][1:]
+valid = {v for _, vs in info for v in vs}
+error_rate = sum(n for row in rest for n in row if n not in valid)
+print(error_rate)
+
+rows = [row for row in rest if valid.issuperset(row)]
+options = [{k for k, vs in info if vs.issuperset(col)} for col in zip(*rows)]
+ans2 = 1
+found = set()
+for k, vs in sorted(enumerate(options), key=lambda pair: len(pair[1])):
+    v, = vs - found
+    found.add(v)
+    if v.startswith('departure'):
+        ans2 *= mine[k]
+print(ans2)