2023-03

Author: Viliam Pucik

2023/03.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+import re
+from collections import defaultdict
+from math import prod
+
+
+def parse(lines):
+    re_number = re.compile(r"\d+")
+    re_symbol = re.compile(r"[^\d.]")
+
+    for y, line in enumerate(lines):
+        for m in re_number.finditer(line):
+            number, x0, x1 = int(m.group()), m.start() - 1, m.end() + 1
+            for yy in range(max(y - 1, 0), min(y + 2, len(lines))):
+                for m in re_symbol.finditer(lines[yy], x0, x1):
+                    yield number, m.group(), m.start(), yy
+
+
+s1, gears = 0, defaultdict(list)
+
+for number, symbol, x, y in parse(open(0).read().splitlines()):
+    s1 += number
+    if symbol == "*":
+        gears[x, y].append(number)
+
+print(s1)
+print(sum(prod(numbers) for numbers in gears.values() if len(numbers) == 2))