2024 day 2.

src/holt59/aoc/2024/day2.py

@@ -1,10 +1,22 @@
 import sys
 
-lines = sys.stdin.read().splitlines()
 
-answer_1 = ...
+def is_safe(level: list[int]) -> bool:
+    diff = [a - b for a, b in zip(level[:-1], level[1:], strict=True)]
 
-answer_2 = ...
+    return sum(d > 0 for d in diff) in (0, len(diff)) and all(
+        1 <= abs(d) <= 3 for d in diff
+    )
+
+
+def is_any_safe(level: list[int]) -> bool:
+    return any(is_safe(level[:i] + level[i + 1 :]) for i in range(0, len(level)))
+
+
+levels = [[int(c) for c in r.split()] for r in sys.stdin.read().splitlines()]
+
+answer_1 = sum(is_safe(level) for level in levels)
+answer_2 = sum(is_safe(level) or is_any_safe(level) for level in levels)
 
 print(f"answer 1 is {answer_1}")
 print(f"answer 2 is {answer_2}")

src/holt59/aoc/inputs/tests/2024/day2.txt

@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9