Add day 10

d10.lua

@@ -0,0 +1,65 @@
+rocks = {}
+pos_y = 0
+for line in io.lines(arg[1]) do
+    pos_x = 0
+    for char in line:gmatch(".") do
+        if char == "#" then
+            table.insert(rocks, {y=pos_y, x=pos_x})
+        end
+        pos_x = pos_x + 1
+    end
+    pos_y = pos_y + 1
+end
+pos_y = nil
+pos_x = nil
+
+max = nil
+for _, rock in ipairs(rocks) do
+    count = 0
+    angles_array = {}
+    angles = {}
+    for _, in_rock in ipairs(rocks) do
+        if rock ~= in_rock then
+            angle = math.atan(in_rock.y - rock.y, in_rock.x - rock.x) + math.pi / 2
+            if angle < 0 then
+                angle = angle + math.pi * 2
+            end
+            if angles[angle] == nil then
+                angles[angle] = {in_rock}
+                table.insert(angles_array, angle)
+                count = count + 1
+            else
+                table.insert(angles[angle], in_rock)
+            end
+        end
+    end
+    if not max or max.count < count then
+        max = {count=count, rock=rock, angles=angles, angles_array=angles_array}
+    end
+end
+
+print(string.format("Part 1: %d (%d,%d)", max.count, max.rock.x, max.rock.y))
+
+table.sort(max.angles_array)
+for _, angle in ipairs(max.angles_array) do
+    table.sort(max.angles[angle], function(x, y)
+        local dist_x = math.sqrt((x.x - max.rock.x) ^ 2 + (x.y - max.rock.y) ^ 2)
+        local dist_y = math.sqrt((y.x - max.rock.x) ^ 2 + (y.y - max.rock.y) ^ 2)
+        return dist_x < dist_y
+    end)
+end
+
+shot = 0
+while true do
+    for _, angle in ipairs(max.angles_array) do
+        if #max.angles[angle] > 0 then
+            shot = shot + 1
+            if shot >= 200 then
+                rock = max.angles[angle][#max.angles[angle]]
+                print(string.format("Part 2: %d", rock.x * 100 + rock.y))
+                os.exit(true)
+            end
+            max.angles[angle][#max.angles[angle]] = nil
+        end
+    end
+end

d10_input.txt

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