
Programming Interview, Clean Code: Longest Common Prefix - sp24oct
http://www.onceaday.today/subjects/10/posts/22
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bauerd

      def common_prefix(strs)
        strs.map(&:chars)
            .reduce(&:zip)
            .map(&:flatten)
            .take_while { |xs| xs.uniq.one? }
            .map(&:uniq)
            .join
      end

