2022: d08: ex2: add solution

2022/d08/ex2/ex2.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+
+import dataclasses
+import sys
+from collections.abc import Iterator
+
+
+@dataclasses.dataclass
+class Point:
+    x: int
+    y: int
+
+
+def solve(input: list[list[int]]) -> int:
+    def up(p: Point) -> Iterator[Point]:
+        x = p.x
+        while (x := x - 1) >= 0:
+            yield Point(x, p.y)
+
+    def down(p: Point) -> Iterator[Point]:
+        x = p.x
+        while (x := x + 1) < len(input):
+            yield Point(x, p.y)
+
+    def left(p: Point) -> Iterator[Point]:
+        y = p.y
+        while (y := y - 1) >= 0:
+            yield Point(p.x, y)
+
+    def right(p: Point) -> Iterator[Point]:
+        y = p.y
+        while (y := y + 1) < len(input[0]):
+            yield Point(p.x, y)
+
+    def visible_trees(p: Point, neighbours: Iterator[Point]) -> Iterator[Point]:
+        height = input[p.x][p.y]
+        for n in neighbours:
+            yield n
+            if height <= input[n.x][n.y]:
+                break
+
+    def score(p: Point) -> int:
+        score = 1
+        for neighbours in (up, down, left, right):
+            score *= len(list(visible_trees(p, neighbours(p))))
+        return score
+
+    scores = [
+        [score(Point(x, y)) for y in range(len(input[x]))] for x in range(len(input))
+    ]
+    return max(map(max, scores))
+
+
+def main() -> None:
+    input = [[int(c) for c in line] for line in sys.stdin.read().splitlines()]
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()