AoC 2024 day 4 part 1

aoc2024/src/day04/python/solution.py

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+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from typing import Sequence
+
+def _extract_all_lines(input: Sequence[str]) -> Sequence[str]:
+    lines = []
+    width = len(input[0])
+    height = len(input)
+    # Horizontals
+    for line in input:
+        lines.append(line)
+    # Verticals
+    for x in range(width):
+        vertical = []
+        for y in range(len(input)):
+            vertical.append(input[y][x])
+        lines.append(''.join(vertical))
+    # Decreasing diagonals
+    for delta in range(-width+2, width):
+        diagonal = []
+        for y in range(height):
+            if 0 <= y+delta < width:
+                diagonal.append(input[y][y+delta])
+        lines.append(''.join(diagonal))
+    # Increasing diagonals
+    for delta in range(-width, width-2):
+        diagonal = []
+        for y in range(height-1, -1, -1):
+            if 0 <= width-y+delta < width:
+                diagonal.append(input[y][width-y+delta])
+        lines.append(''.join(diagonal))
+    return lines
+
+def count_xmas_words(input: Sequence[str]) -> int:
+    lines = _extract_all_lines(input)
+    return sum(line.count('XMAS') for line in lines) + sum(line.count('SAMX') for line in lines)

aoc2024/test/day04/python/example1.txt

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+..X...
+.SAMX.
+.A..A.
+XMAS.S
+.X....

aoc2024/test/day04/python/example2.txt

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+....XXMAS.
+.SAMXMS...
+...S..A...
+..A.A.MS.X
+XMASAMX.MM
+X.....XA.A
+S.S.S.S.SS
+.A.A.A.A.A
+..M.M.M.MM
+.X.X.XMASX

aoc2024/test/day04/python/test_solution.py

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+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import unittest
+
+from aoc2024.src.day04.python.solution import count_xmas_words
+from common.python3.AdventOfCodeTestCase import AdventOfCodeTestCase
+
+
+class TestDay04Solution(AdventOfCodeTestCase):
+  def __init__(self, *args, **kwargs):
+    (super(TestDay04Solution, self).__init__(__file__, *args, **kwargs))
+
+  def test_part1_withExample_counts(self):
+    self.assertEqual(4, count_xmas_words(self.examples[0]))
+
+  def test_part1_withExample2_counts(self):
+    self.assertEqual(18, count_xmas_words(self.examples[1]))
+
+  def test_part1_withPuzzleInput_counts(self):
+    self.assertEqual(2603, count_xmas_words(self.input))
+
+
+if __name__ == '__main__':
+  unittest.main()