Python: Day 4 solution

04/py/solution.py

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+import operator
+from collections.abc import Callable
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass(frozen=True, slots=True)
+class Range:
+    lower: int
+    upper: int
+
+    @classmethod
+    def from_pair(cls, s: str) -> "Range":
+        left, right = [int(num) for num in s.split("-")]
+        return cls(left, right)
+
+    @staticmethod
+    def _compare(a: "Range", b: "Range", _op: Callable[[bool, bool], bool]):
+        if _op(
+            b.lower <= a.lower <= b.upper,
+            b.lower <= a.upper <= b.upper,
+        ):
+            return True
+
+        if _op(
+            a.lower <= b.lower <= a.upper,
+            a.lower <= b.upper <= a.upper,
+        ):
+            return True
+
+        return False
+
+    def fully_contains(self, other: "Range") -> bool:
+        return Range._compare(self, other, operator.and_)
+
+    def overlaps(self, other: "Range") -> bool:
+        return Range._compare(self, other, operator.or_)
+
+
+def part1(data: str) -> int:
+    count = 0
+    for line in data.splitlines():
+        left, right = [Range.from_pair(s) for s in line.split(",")]
+        if left.fully_contains(right):
+            count += 1
+    return count
+
+
+def part2(data: str) -> int:
+    count = 0
+    for line in data.splitlines():
+        left, right = [Range.from_pair(s) for s in line.split(",")]
+        if left.overlaps(right):
+            count += 1
+    return count
+
+
+# Setup
+data = (Path(__file__).parents[1] / "input").read_text()
+
+# Problem solving - part 1
+result = part1(data)
+print(f"Part 1 solution: {result}")
+
+# Problem solving - part 2
+result = part2(data)
+print(f"Part 2 solution: {result}")