Day 10 - Part 1

Day10/Day10.cs

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+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace Advent
+{
+    public static class Day10
+    {
+        public static void Execute()
+        {
+            var lines = File.ReadAllLines(@".\Day10\input.txt");
+
+            var y = 0;
+
+            var asteroids = new List<Tuple<int, int>>();
+
+            foreach (var line in lines)
+            {
+                var x = 0;
+
+                foreach (var cell in line.ToCharArray())
+                {
+                    if (cell == '#')
+                        asteroids.Add(new Tuple<int, int>(x, y));
+
+                    x++;
+                }
+
+                y++;
+            }
+
+            var bestLocation = new Tuple<int, int>(-1, -1);
+            var bestCount = 0;
+
+            foreach (var potentialAsteroid in asteroids)
+            {
+                var angles = new HashSet<double>();
+
+                foreach (var asteroid in asteroids)
+                {
+                    if (asteroid.Equals(potentialAsteroid))
+                        continue;
+
+                    var angle = Math.Atan2(asteroid.Item2 - potentialAsteroid.Item2, asteroid.Item1 - potentialAsteroid.Item1);
+
+                    if (!angles.Contains(angle))
+                        angles.Add(angle);
+                }
+
+                if (angles.Count > bestCount)
+                {
+                    bestCount = angles.Count;
+                    bestLocation = potentialAsteroid;
+                }
+            }
+
+            Console.WriteLine($"{bestLocation.Item1},{bestLocation.Item2} = {bestCount}");
+        }
+    }
+}

Day10/input.txt

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+.##.#.#....#.#.#..##..#.#.
+#.##.#..#.####.##....##.#.
+###.##.##.#.#...#..###....
+####.##..###.#.#...####..#
+..#####..#.#.#..#######..#
+.###..##..###.####.#######
+.##..##.###..##.##.....###
+#..#..###..##.#...#..####.
+....#.#...##.##....#.#..##
+..#.#.###.####..##.###.#.#
+.#..##.#####.##.####..#.#.
+#..##.#.#.###.#..##.##....
+#.#.##.#.##.##......###.#.
+#####...###.####..#.##....
+.#####.#.#..#.##.#.#...###
+.#..#.##.#.#.##.#....###.#
+.......###.#....##.....###
+#..#####.#..#..##..##.#.##
+##.#.###..######.###..#..#
+#.#....####.##.###....####
+..#.#.#.########.....#.#.#
+.##.#.#..#...###.####..##.
+##...###....#.##.##..#....
+..##.##.##.#######..#...#.
+.###..#.#..#...###..###.#.
+#..#..#######..#.#..#..#.#