day 14

Author: r0f1

README.md

@@ -15,7 +15,7 @@
 |[11](https://adventofcode.com/2020/day/11)|Seating System|[py](/day11/main.py)|
 |[12](https://adventofcode.com/2020/day/12)|Rain Risk|[py](/day12/main.py)|
 |[13](https://adventofcode.com/2020/day/13)|Shuttle Search|[py](/day13/main.py)|
-|[14](https://adventofcode.com/2020/day/14)|-|-|
+|[14](https://adventofcode.com/2020/day/14)|Docking Data|[py](/day14/main.py)|
 |[15](https://adventofcode.com/2020/day/15)|-|-|
 |[16](https://adventofcode.com/2020/day/16)|-|-|
 |[17](https://adventofcode.com/2020/day/17)|-|-|

day14/main.py

@@ -0,0 +1,29 @@
+from itertools import product
+from parse import search
+
+def possible_addrs(mask, addr):
+    mask2 = "".join(v if m == "0" else m for m, v in zip(mask, f"{addr:036b}"))
+    res = []
+    for t in product("01", repeat=mask2.count("X")):
+        it = iter(t)
+        res.append(int("".join(next(it) if c == "X" else c for c in mask2), 2))
+    return res
+
+with open("input.txt") as f:
+    lines = [x.strip() for x in f]
+
+for is_part1 in [True, False]:
+    mask = ""
+    mem = {}
+    for line in lines:
+        if line.startswith("mask"):
+            mask = line.split(" = ")[1]
+        else:
+            arg1, arg2 = search("mem[{:d}] = {:d}", line).fixed
+            if is_part1:
+                mem[arg1] = int("".join(v if m == "X" else m for m, v in zip(mask, f"{arg2:036b}")), 2)
+            else:
+                for addr in possible_addrs(mask, arg1):
+                    mem[addr] = arg2
+
+    print(sum(mem.values()))