# HG changeset patch
# User IBBoard <dev@ibboard.co.uk>
# Date 1702722576 0
# Node ID 46fb65f2cb94180bc29c793fa2784d61ead0c14f
# Parent  fac484765bc964248d6d0e08f17bcb17fa9b750f
Add Day 14 part 1 implementation

If you look at columns and see "how far can this go" then the
weight is just the sum of the partial triangle numbers of
highest_weight to highest_weight minus number of rocks that
can roll up to there.

Part 2 seems to involve actually moving the rocks, though!

diff -r fac484765bc9 -r 46fb65f2cb94 day14.rb
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/day14.rb	Sat Dec 16 10:29:36 2023 +0000
@@ -0,0 +1,27 @@
+#! /usr/bin/env ruby
+
+if ARGV.length != 1
+        abort("Incorrect arguments - needs input file")
+elsif not File.exist? (ARGV[0])
+	abort("File #{ARGV[0]} did not exist")
+end
+
+file = ARGV[0]
+
+platform = File.open(file, "r").each_line(chomp: true).map {|row| row.each_char.to_a}.to_a.transpose()
+
+COL_SIZE = platform[0].length
+
+chunked_platform = platform.map {|col| col.chunk_while {|i, j| i != "#"}.to_a}
+total_load = chunked_platform.reduce(0) do |weight, col|
+	_, col_weight = col.reduce([COL_SIZE, 0]) do |accum, chunk|
+		first_obj_weight, temp_weight = accum
+		num_moved_objs = chunk.count("O")
+		last_obj_weight = first_obj_weight - num_moved_objs
+		temp_weight += ((first_obj_weight * (first_obj_weight + 1)) / 2) - ((last_obj_weight * (last_obj_weight + 1)) / 2)
+		first_obj_weight -= chunk.length
+		[first_obj_weight, temp_weight]
+	end
+	weight + col_weight
+end
+puts total_load
\ No newline at end of file
diff -r fac484765bc9 -r 46fb65f2cb94 day14.txt
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/day14.txt	Sat Dec 16 10:29:36 2023 +0000
@@ -0,0 +1,92 @@
+--- Day 14: Parabolic Reflector Dish ---
+
+Given movable objects (O) and stationary objects (#) with free space (.),
+"tilt" the map to the top so that the movable objects slide to the top
+of the map and then determine the total "load" - the sum of the number
+of rows from the movable object to the bottom of the map.
+
+Given:
+
+O....#....
+O.OO#....#
+.....##...
+OO.#O....O
+.O.....O#.
+O.#..O.#.#
+..O..#O..O
+.......O..
+#....###..
+#OO..#....
+
+Sliding makes it:
+
+OOOO.#.O..
+OO..#....#
+OO..O##..O
+O..#.OO...
+........#.
+..#....#.#
+..O..#.O.O
+..O.......
+#....###..
+#....#....
+
+The load calculation is:
+
+OOOO.#.O.. 10
+OO..#....#  9
+OO..O##..O  8
+O..#.OO...  7
+........#.  6
+..#....#.#  5
+..O..#.O.O  4
+..O.......  3
+#....###..  2
+#....#....  1
+
+Which gives 136.
+
+Given a huge map, what is the load?
+
+--- Part 2 ---
+
+Now we want to cycle them by shifting them all in a cycle north, west, south and east.
+
+After 1 cycle:
+.....#....
+....#...O#
+...OO##...
+.OO#......
+.....OOO#.
+.O#...O#.#
+....O#....
+......OOOO
+#...O###..
+#..OO#....
+
+After 2 cycles:
+.....#....
+....#...O#
+.....##...
+..O#......
+.....OOO#.
+.O#...O#.#
+....O#...O
+.......OOO
+#..OO###..
+#.OOO#...O
+
+After 3 cycles:
+.....#....
+....#...O#
+.....##...
+..O#......
+.....OOO#.
+.O#...O#.#
+....O#...O
+.......OOO
+#...O###.O
+#.OOO#...O
+
+
+What is the top load after 1,000,000,000 cycles?
\ No newline at end of file