CodeEval - Swap Numbers

Swap Numbers - CodeEval
汚い。

swap_numbers.rb

File.open(ARGV[0]).each_line {|line|
    input_line = line.chomp.split(" ")
    output_line = []
    input_line.each{|word|
        swap     = word.dup
        swap[0]  = word[-1]
        swap[-1] = word[0]
        output_line << swap
    }
    puts output_line.join(" ")
}