Add solution to 2024-12-04

Author: fuglede

2024/day04/solutions.py

@@ -0,0 +1,38 @@
+from collections import defaultdict
+from itertools import product
+
+with open("input") as f:
+    ls = f.read().strip().split("\n")
+
+
+boardz = defaultdict(str)
+boardz |= {i + 1j * j: x for i, l in enumerate(ls) for j, x in enumerate(l)}
+octdir = {i + 1j * j for (i, j) in set(product((-1, 0, 1), (-1, 0, 1))) - {(0, 0)}}
+
+# Part 1
+print(
+    sum(
+        [boardz[z + i * dz] for i in range(4)] == ["X", "M", "A", "S"]
+        for z in list(boardz.keys())
+        for dz in octdir
+    )
+)
+
+
+# Part 2
+res = 0
+for z in list(boardz.keys()):
+    if boardz[z] == "A":
+        corners = [
+            boardz[z + 1 + 1j],
+            boardz[z + 1 - 1j],
+            boardz[z - 1 - 1j],
+            boardz[z - 1 + 1j],
+        ]
+        if (
+            corners.count("M") == 2
+            and corners.count("S") == 2
+            and boardz[z - 1 - 1j] != boardz[z + 1 + 1j]
+        ):
+            res += 1
+print(res)