From 20546f5e813656fe8e003a3c6a469c4f6e272096 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Wed, 11 Dec 2019 16:37:36 +0100
Subject: [PATCH] 2019: d10: ex1: clean-up solution

---
 2019/d10/ex1/ex1.py | 76 ++++++++++++++-------------------------------
 1 file changed, 23 insertions(+), 53 deletions(-)

diff --git a/2019/d10/ex1/ex1.py b/2019/d10/ex1/ex1.py
index 79f1ed4..eb538df 100755
--- a/2019/d10/ex1/ex1.py
+++ b/2019/d10/ex1/ex1.py
@@ -1,79 +1,49 @@
 #!/usr/bin/env python
 
 import sys
-from itertools import chain
 from math import gcd
-from typing import Set, Tuple
+from typing import NamedTuple, Set
 
-Position = Tuple[int, int]
+
+class Position(NamedTuple):
+    x: int
+    y: int
 
 
 def main() -> None:
-    asteroids = [[c == "#" for c in line.rstrip()] for line in sys.stdin.readlines()]
-
-    def count_spotted(i: int, j: int) -> int:
-        def is_valid(pos: Position) -> bool:
-            return 0 <= pos[0] < len(asteroids) and 0 <= pos[1] < len(asteroids[0])
-
-        def pos_around(radius: int) -> Set[Position]:
-            return set(
-                chain(
-                    filter(
-                        is_valid,
-                        (
-                            (i - offset, j - radius)
-                            for offset in range(-radius, radius + 1)
-                        ),
-                    ),
-                    filter(
-                        is_valid,
-                        (
-                            (i - offset, j + radius)
-                            for offset in range(-radius, radius + 1)
-                        ),
-                    ),
-                    filter(
-                        is_valid,
-                        (
-                            (i - radius, j - offset)
-                            for offset in range(-radius, radius + 1)
-                        ),
-                    ),
-                    filter(
-                        is_valid,
-                        (
-                            (i + radius, j - offset)
-                            for offset in range(-radius, radius + 1)
-                        ),
-                    ),
-                )
-            )
+    asteroids = [
+        Position(x, y)
+        for y, line in enumerate(sys.stdin.readlines())
+        for x, c in enumerate(line.rstrip())
+        if c == "#"
+    ]
 
+    def count_spotted(x: int, y: int) -> int:
         seen: Set[Position] = set()
         ans = 0
         radius = 1
-        while asteroids[i][j]:  # Only do this if are on an asteroid
-            to_visit = pos_around(radius)
+
+        while True:
+
+            def is_r_away(pos: Position) -> bool:
+                return max(abs(pos.x - x), abs(pos.y - y)) == radius
+
+            to_visit = list(filter(is_r_away, asteroids))
             radius += 1
             if len(to_visit) == 0:
                 break
             for pos in to_visit:
-                if not asteroids[pos[0]][pos[1]]:
-                    continue  # No asteroid there
-                rel = (pos[0] - i, pos[1] - j)
+                rel = (pos.x - x, pos.y - y)
                 common = gcd(*rel)
-                rel = (rel[0] // common, rel[1] // common)
+                rel = Position(*(a // common for a in rel))
                 if rel in seen:
                     continue  # Already have an asteroid on this path
                 seen.add(rel)
                 ans += 1
+
         return ans
 
-    ans, y, x = max(
-        (count_spotted(i, j), i, j)
-        for i in range(len(asteroids))
-        for j in range(len(asteroids[0]))
-    )
+    ans, x, y = max((count_spotted(*pos), *pos) for pos in asteroids)
     print(f"({x}, {y}): {ans}")