[day05] done, naïve and slow

1 files changed, 34 insertions, 0 deletions

diff --git a/day05/part2 b/day05/part2
new file mode 100755
index 0000000..b71d84e
--- /dev/null
+++ b/day05/part2
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+#!/usr/bin/env ruby
+
+input = gets.chomp.chars
+
+units = input.map(&:downcase).uniq
+lengths = {}
+
+units.each do |unit|
+  polymer = input.dup
+  polymer.delete_if {|u| u == unit || u == unit.upcase}
+  l = polymer.length
+  loop do
+    i = polymer.length - 1
+    loop do
+      break if i < 1
+
+      if polymer[i] == polymer[i-1].swapcase
+        polymer.delete_at(i)
+        polymer.delete_at(i-1)
+        i -= 2
+      else
+        i -= 1
+      end
+    end
+    if polymer.length == l
+      break
+    else
+      l = polymer.length
+    end
+  end
+  lengths[unit] = polymer.length
+end
+
+puts lengths.values.min