2024: Day 4

Author: MiLk

2024/python/day4/__init__.py

@@ -0,0 +1,54 @@
+import re
+from itertools import product
+
+from utils.file import read_input
+
+lines: list[str] = read_input(__package__)
+
+
+class WordMatcher:
+    def __init__(self, words: set[str]) -> None:
+        self._words = words
+        self._count = 0
+
+    def check(self, word: str) -> None:
+        if word in self._words:
+            self._count += 1
+
+    @property
+    def count(self) -> int:
+        return self._count
+
+
+word_matcher = WordMatcher({"XMAS", "SAMX"})
+
+h, w = len(lines), len(lines[0])
+for i, j in product(range(h), range(w)):
+    if j < w - 3:
+        candidate_right = lines[i][j : j + 4]
+        word_matcher.check(lines[i][j : j + 4])
+
+    if i < h - 3:
+        candidate_down = "".join(lines[i + k][j] for k in range(4))
+        word_matcher.check(candidate_down)
+
+    if i < h - 3 and j < w - 3:
+        candidate_down_right = "".join(lines[i + k][j + k] for k in range(4))
+        word_matcher.check(candidate_down_right)
+
+    if j >= 3 and i < h - 3:
+        candidate_down_left = "".join(lines[i + k][j - k] for k in range(4))
+        word_matcher.check(candidate_down_left)
+
+print("Part 1:", word_matcher.count)
+
+count2 = 0
+EXPECTED_CORNERS = {"MMSS", "MSSM", "SSMM", "SMMS"}
+for i, j in product(range(1, h - 1), range(1, w - 1)):
+    if lines[i][j] != "A":
+        continue
+    corners = "".join([lines[i - 1][j - 1], lines[i - 1][j + 1], lines[i + 1][j + 1], lines[i + 1][j - 1]])
+    if corners in EXPECTED_CORNERS:
+        count2 += 1
+
+print("Part 1:", count2)