2020: d14: ex1: add solution

2020/d14/ex1/ex1.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+import re
+import sys
+from dataclasses import dataclass
+from typing import Dict, List
+
+
+@dataclass
+class Mask:
+    ones: int
+    zeros: int
+
+
+Memory = Dict[int, int]
+
+
+def solve(raw: List[str]) -> int:
+    mask = Mask(
+        0,
+        (2 << 36) - 1,
+    )
+    mem_pattern = re.compile("mem\\[([0-9]+)\\] = ([0-9]+)")
+    mask_pattern = re.compile("mask = ([01X]+)")
+    mem: Memory = {}
+    for instr in raw:
+        if (mem_match := mem_pattern.match(instr)) is not None:
+            addr, val = int(mem_match.group(1)), int(mem_match.group(2))
+            val |= mask.ones
+            val &= mask.zeros
+            mem[addr] = val
+        elif (mask_match := mask_pattern.match(instr)) is not None:
+            ones = int(mask_match.group(1).replace("X", "0"), 2)
+            zeros = int(mask_match.group(1).replace("X", "1"), 2)
+            mask = Mask(ones, zeros)
+    return sum(mem.values())
+
+
+def main() -> None:
+    input = [line.strip() for line in sys.stdin.readlines()]
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()