[2022][ruby][14.x]

2022/ruby/day_14.rb

@@ -0,0 +1,62 @@
+scan = ARGF.read.lines(chomp: true)
+
+cave = scan.each.with_object({}) {|line, cave|
+  line.split(" -> ")
+    .map { _1.split(?,).map(&:to_i) }
+    .each_cons(2) {|(ax,ay),(bx,by)|
+      Range.new(*[ax, bx].sort).each do |x|
+        Range.new(*[ay, by].sort).each do |y|
+          cave[[x, y]] = ?#
+        end
+      end
+    }
+}
+
+x_min, x_max = cave.keys.map(&:first).minmax
+y_min, y_max = cave.keys.map(&:last).minmax
+
+inspect_cave = -> {
+  puts (0..y_max+1).map {|y|
+    (x_min-1..x_max+1).map {|x|
+      cave[[x, y]] || ?.
+    }.join
+  }.join("\n")
+}
+
+# part one
+# sands = 0
+# loop do
+#   inspect_cave.()
+#   sands += 1
+
+#   pos = [500, 0]
+#   while next_pos = [0, -1, 1].map {|dx| pos.zip([dx, 1]).map { _1 + _2 }}.find { cave[_1].nil? }
+#     pos = next_pos
+#     break if pos[1] >= y_max
+#   end
+#   break if pos[1] >= y_max
+
+#   cave[pos] = ?o
+# end
+
+# inspect_cave.()
+# p sands-1
+
+# part two
+cave.default_proc = ->(h,(x,y)) { h[[x, y]] = y == y_max + 2 ? ?# : nil }
+sands = 0
+loop do
+  # inspect_cave.()
+  sands += 1
+
+  pos = [500, 0]
+  while next_pos = [0, -1, 1].map {|dx| pos.zip([dx, 1]).map { _1 + _2 }}.find { cave[_1].nil? }
+    pos = next_pos
+  end
+  break if pos == [500, 0]
+
+  cave[pos] = ?o
+end
+
+inspect_cave.()
+p sands