From 75a8595e4d11af5cb650844978c87348e0fa42fa Mon Sep 17 00:00:00 2001
From: Thomas Voss <thomasvoss@live.com>
Date: Thu, 2 Dec 2021 08:52:32 +0100
Subject: Use python3.10 pattern matching
---
2015/19/puzzle-1.py | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
(limited to '2015/19')
diff --git a/2015/19/puzzle-1.py b/2015/19/puzzle-1.py
index 8527ca0..b694c8b 100755
--- a/2015/19/puzzle-1.py
+++ b/2015/19/puzzle-1.py
@@ -2,29 +2,30 @@
import re
+
def main() -> None:
replacements: dict[str, str] = {}
with open("input", "r", encoding="utf-8") as f:
for line in f.readlines():
- line = line.strip()
- if line != "":
- parts = line.split(" => ")
- if len(parts) == 2:
- while parts[0] in replacements:
- parts[0] += "_"
- replacements[parts[0]] = parts[1]
- else:
- molecule = line
+ match line.strip().split(" => "):
+ case [before, after]:
+ while before in replacements:
+ before += "_"
+ replacements[before] = after
+ case [mol]:
+ molecule = mol
unique_molecules: set[str] = set()
for pattern in replacements:
- trim_pattern = pattern.replace("_", "")
- for match in re.finditer(trim_pattern, molecule):
- before = molecule[:match.start()]
- after = molecule[match.start():].replace(trim_pattern, replacements[pattern], 1)
- unique_molecules.add(before + after)
-
+ trim_pattern = pattern.rstrip("_")
+ unique_molecules.update(
+ molecule[: match.start()]
+ + molecule[match.start() :].replace(trim_pattern, replacements[pattern], 1)
+ for match in re.finditer(trim_pattern, molecule)
+ )
+
print(len(unique_molecules))
+
if __name__ == "__main__":
main()
--
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