From f6c24e698cff124ba396d2e88f39337e64caa0fe Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Tue, 3 Dec 2024 10:13:19 +0000
Subject: [PATCH] 2024: d03: ex2: add solution

---
 2024/d03/ex2/ex2.py | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100755 2024/d03/ex2/ex2.py

diff --git a/2024/d03/ex2/ex2.py b/2024/d03/ex2/ex2.py
new file mode 100755
index 0000000..f85fb47
--- /dev/null
+++ b/2024/d03/ex2/ex2.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+import dataclasses
+import re
+import sys
+
+
+@dataclasses.dataclass
+class MulInstruction:
+    lhs: int
+    rhs: int
+
+    def calc(self) -> int:
+        return self.lhs * self.rhs
+
+
+def solve(input: str) -> int:
+    def parse(input: str) -> list[MulInstruction]:
+        res: list[MulInstruction] = []
+
+        MUL_REGEX = re.compile(r"do\(\)|don't\(\)|mul\((\d+),(\d+)\)")
+        do = True
+        for match in MUL_REGEX.finditer(input):
+            if match.group(0) in ("do()", "don't()"):
+                do = match.group(0) == "do()"
+                continue
+            if not do:
+                continue
+            res.append(MulInstruction(int(match.group(1)), int(match.group(2))))
+
+        return res
+
+    return sum(inst.calc() for inst in parse(input))
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()