GCJ 2011 CandySplitting problem

gcj_solver.rb

class GCJSolution
  def initialize(input = STDIN, output = STDOUT)
    @input = input
    @output = output
  end
  
  def read_strings
    @input.gets.chomp.split(' ')
  end

  def read_ints
    read_strings.map(&:to_i)
  end
  
  def read_int
    @input.gets.to_i
  end
  
  def read_solve_write_all
    number_of_tests = read_int
    for test_no in 1..number_of_tests
      test_case = parse_input()
      ans = solve(test_case)
      @output.puts "Case ##{test_no}: #{ans}"
    end
    number_of_tests
  end
end

class CandySplitting < GCJSolution
  def parse_input
    read_int
    read_ints
  end
  
  def solve(a)
    xor = a.inject(0, &:^)
    if xor == 0
      sum = a.inject(0, &:+)
      sum - a.min
    else
      'NO'
    end
  end
end

CandySplitting.new.read_solve_write_all