Initial commit with days 1 to 4.

day2/solver.py

@@ -0,0 +1,69 @@
+from typing import Callable, Iterator
+import sys
+
+
+def check_report_basic(levels: tuple[int, ...]) -> bool:
+    safe = True
+    differences = [next_level - level for level, next_level in zip(levels, levels[1:])]
+    safe = safe and (
+        all(-3 <= diff <= -1 for diff in differences)
+        or all(1 <= diff <= 3 for diff in differences)
+    )
+    return safe
+
+def check_report_damp(levels: tuple[int, ...]) -> bool:
+    # Obvious solution is using check_report_basic iteratively..
+    # Is there a better solution?
+    safe = check_report_basic(levels)
+    safe = safe or any(check_report_basic(levels[:i] + levels[i+1:]) for i in range(len(levels)))
+    return safe
+
+def tester(data: dict[tuple[int, ...], bool], checker: Callable[[tuple[int, ...]], bool]):
+    for report, expected in data.items():
+        assert (checker(report) is expected), f"Check failed: {report=} should be {expected=}"
+
+def tests():
+    print("Testing basic check")
+    data = {
+        (7, 6, 4, 2, 1): True,
+        (1, 2, 7, 8, 9): False,
+        (9, 7, 6, 2, 1): False,
+        (1, 3, 2, 4, 5): False,
+        (8, 6, 4, 4, 1): False,
+        (1, 3, 6, 7, 9): True,
+    }
+    tester(data, check_report_basic)
+    print("Basic check passed.")
+
+    print("Testing dampened check.")
+    data = {
+        (7, 6, 4, 2, 1): True,
+        (1, 2, 7, 8, 9): False,
+        (9, 7, 6, 2, 1): False,
+        (1, 3, 2, 4, 5): True,
+        (8, 6, 4, 4, 1): True,
+        (1, 3, 6, 7, 9): True,
+    }
+    tester(data, check_report_damp)
+    print("Damp check passed.")
+
+def main():
+    tests()
+    filename = sys.argv[1]
+    reports = load_data(filename)
+    total = sum(map(check_report_basic, reports))
+    print(f"Total safe reports without damping: {total}")
+
+    reports = load_data(filename)
+    total = sum(map(check_report_damp, reports))
+    print(f"Total safe reports with damping: {total}")
+
+
+def load_data(filename) -> Iterator[tuple[int, ...]]:
+    with open(filename) as f:
+        for line in f:
+            if line.strip():
+                yield tuple(map(int, line.split()))
+
+if __name__ == '__main__':
+    main()