day08 finished

advent/days/day08/solution.py

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+from __future__ import annotations
+from dataclasses import dataclass
+
+from typing import Iterator
+
+day_num = 8
+
+
+def part1(lines: Iterator[str]) -> int:
+    return Trees.parse(lines).count_visible()
+
+
+def part2(lines: Iterator[str]) -> int:
+    return Trees.parse(lines).max_scenic_score()
+
+
+@dataclass(slots=True)
+class Trees:
+    trees: list[list[int]]
+    width: int
+    height: int
+
+    @staticmethod
+    def parse(lines: Iterator[str]) -> Trees:
+        trees = [[int(tree) for tree in line] for line in lines]
+        return Trees(trees, len(trees[0]), len(trees))
+
+    def count_visible(self) -> int:
+        visible = [[True] * self.width]
+        for _ in range(self.height - 2):
+            visible += [[True] + [False] * (self.width - 2) + [True]]
+        visible += [[True] * self.width]
+
+        # From Up
+        mx = self.trees[0].copy()
+        for y in range(1, self.height - 1):
+            for x in range(1, self.width - 1):
+                if self.trees[y][x] > mx[x]:
+                    mx[x] = self.trees[y][x]
+                    visible[y][x] = True
+
+        # From Down
+        mx = self.trees[-1].copy()
+        for y in range(self.height - 2, 0, -1):
+            for x in range(1, self.width - 1):
+                if self.trees[y][x] > mx[x]:
+                    mx[x] = self.trees[y][x]
+                    visible[y][x] = True
+
+        # From Left
+        mx = [self.trees[y][0] for y in range(self.height)]
+        for x in range(1, self.width - 1):
+            for y in range(1, self.height - 1):
+                if self.trees[y][x] > mx[y]:
+                    mx[y] = self.trees[y][x]
+                    visible[y][x] = True
+
+        # From Right
+        mx = [self.trees[y][-1] for y in range(self.height)]
+        for x in range(self.width - 2, 0, -1):
+            for y in range(1, self.height - 1):
+                if self.trees[y][x] > mx[y]:
+                    mx[y] = self.trees[y][x]
+                    visible[y][x] = True
+
+        return sum(1 for y in range(self.height) for x in range(self.width) if visible[y][x])
+
+    def max_scenic_score(self) -> int:
+        max_score = 0
+        for y in range(1, self.height - 1):
+            for x in range(1, self.width - 1):
+                score = self.single_scenic_score(x, y)
+                if score > max_score:
+                    max_score = score
+        return max_score
+
+    def single_scenic_score(self, x: int, y: int) -> int:
+        up = 0
+        for dy in range(y - 1, -1, -1):
+            up += 1
+            if self.trees[dy][x] >= self.trees[y][x]:
+                break
+
+        down = 0
+        for dy in range(y + 1, self.height):
+            down += 1
+            if self.trees[dy][x] >= self.trees[y][x]:
+                break
+
+        left = 0
+        for dx in range(x - 1, -1, -1):
+            left += 1
+            if self.trees[y][dx] >= self.trees[y][x]:
+                break
+
+        right = 0
+        for dx in range(x + 1, self.width):
+            right += 1
+            if self.trees[y][dx] >= self.trees[y][x]:
+                break
+
+        return up * down * left * right