day 2 - part 2

src/aoc_2024/day2/part1.py

@@ -25,14 +25,6 @@ def is_report_safe(report: list[int]) -> bool:
     return True
 
 
-def get_records(input_file: Path) -> list[list[int]]:
-    records = []
-    for line in input_file.open():
-        record = [int(i) for i in line.strip().split(" ")]
-        records.append(record)
-    return records
-
-
 def get_reports(input_file: Path) -> list[list[int]]:
     reports = []
     for line in input_file.open():

src/aoc_2024/day2/part2.py

@@ -0,0 +1,61 @@
+from pathlib import Path
+
+
+def is_report_safe(report: list[int]) -> bool:
+    try:
+        is_increasing = True
+        is_decreasing = True
+        for i in range(len(report)):
+            shift = report[i + 1] - report[i]
+            if shift == 0:
+                is_increasing = False
+                is_decreasing = False
+            if shift > 0:
+                is_decreasing = False
+            if shift < 0:
+                is_increasing = False
+
+            if not is_decreasing and not is_increasing:
+                return False
+
+            if abs(shift) > 3:
+                return False
+    except IndexError:
+        pass
+    return True
+
+
+def is_report_safe_with_tolerance(report: list[int]) -> bool:
+    for i in range(len(report)):
+        tmp_report = list(report)
+        tmp_report.pop(i)
+        is_safe = is_report_safe(tmp_report)
+        if is_safe:
+            return True
+    return False
+
+
+def get_reports(input_file: Path) -> list[list[int]]:
+    reports = []
+    for line in input_file.open():
+        report = [int(r) for r in line.strip().split(" ")]
+        reports.append(report)
+    return reports
+
+
+def main(data_file: Path):
+    reports = get_reports(data_file)
+    score = 0
+    for report in reports:
+        if is_report_safe(report):
+            score += 1
+        else:
+            if is_report_safe_with_tolerance(report):
+                score += 1
+    print(score)
+    return score
+
+
+if __name__ == "__main__":
+    file = Path(__file__).parent / "input-data"
+    main(file)

tests/aoc_2024/day2/test-part2.py

@@ -0,0 +1,68 @@
+from pathlib import Path
+
+from aoc_2024.day2 import part2
+
+
+def test_report_with_tolerance_with_decreasing_levels_less_than_3_is_safe():
+    report = [7, 6, 4, 2, 1]
+    assert part2.is_report_safe_with_tolerance(report)
+
+
+def test_report_with_tolerance_with_decreasing_levels_more_than_3_is_not_safe():
+    report = [9, 7, 6, 2, 1]
+    assert not part2.is_report_safe_with_tolerance(report)
+
+
+def test_report_with_tolerance_without_increasing_or_decreasing_levels_is_not_safe():
+    report = [8, 6, 4, 4, 1]
+    assert part2.is_report_safe_with_tolerance(report)
+
+
+def test_report_with_tolerance_with_increasing_and_decreasing_levels_is_not_safe():
+    report = [1, 3, 2, 4, 5]
+    assert part2.is_report_safe_with_tolerance(report)
+
+
+def test_report_with_tolerance_with_increasing_levels_less_than_3_is_safe():
+    report = [1, 3, 6, 7, 9]
+    assert part2.is_report_safe_with_tolerance(report)
+
+
+def test_report_with_tolerance_with_increasing_levels_more_than_3_is_not_safe():
+    report = [1, 2, 7, 8, 9]
+    assert not part2.is_report_safe_with_tolerance(report)
+
+
+def test_report_with_decreasing_levels_less_than_3_is_safe():
+    report = [7, 6, 4, 2, 1]
+    assert part2.is_report_safe(report)
+
+
+def test_report_with_decreasing_levels_more_than_3_is_not_safe():
+    report = [9, 7, 6, 2, 1]
+    assert not part2.is_report_safe(report)
+
+
+def test_report_without_increasing_or_decreasing_levels_is_not_safe():
+    report = [8, 6, 4, 4, 1]
+    assert not part2.is_report_safe(report)
+
+
+def test_report_with_increasing_and_decreasing_levels_is_not_safe():
+    report = [1, 3, 2, 4, 5]
+    assert not part2.is_report_safe(report)
+
+
+def test_report_with_increasing_levels_less_than_3_is_safe():
+    report = [1, 3, 6, 7, 9]
+    assert part2.is_report_safe(report)
+
+
+def test_report_with_increasing_levels_more_than_3_is_not_safe():
+    report = [1, 2, 7, 8, 9]
+    assert not part2.is_report_safe(report)
+
+
+def test_read_records_file():
+    test_file = Path(__file__).parent / "test-data"
+    assert part2.main(test_file) == 4