day 14, part 1

wheeee naive repeatative mapping and string transforms!
Almost certainly not set up for success in part 2! ᕕ( ᐛ )ᕗ

Author: Robb Kidd

2023/ruby/day14.rb

@@ -0,0 +1,50 @@
+require_relative 'day'
+
+class Day14 < Day # >
+
+  # @example
+  #   day.part1 #=> 136
+  def part1
+    columns =
+      input
+        .split("\n")
+        .map(&:chars)
+        .transpose      # pivot so that each array is a column
+        .reject {|column| !column.include?("O") } # don't bother with columns that don't have rounded rocks
+        .map(&:join)    # make it a string again
+        .map { |column|
+          column
+            .reverse              # north is now towards the end of the string
+            .split("#", -1)       # find the stretches between cube rocks, keep trailing empties
+            .map { |substring|
+              substring.chars.sort.join # roll rocks within stretches
+            }
+            .join("#")                  # put the cubes back in
+
+        }
+        .map { |rolled_column|
+              (0..rolled_column.length)
+                .filter_map {|i| i+1 if rolled_column[i] == "O"}
+                .reduce(&:+)
+            }
+        .reduce(&:+)
+  end
+
+  # example
+  #   day.part2 #=> 'how are you'
+  def part2
+  end
+
+  EXAMPLE_INPUT = <<~INPUT
+    O....#....
+    O.OO#....#
+    .....##...
+    OO.#O....O
+    .O.....O#.
+    O.#..O.#.#
+    ..O..#O..O
+    .......O..
+    #....###..
+    #OO..#....
+  INPUT
+end