gistfile1.rb

class ArrayCalculator
  
  TEST_ONE = [-7, 1, 5, 2, -4, 3, 0]
  TEST_TWO = [-7, 1, 5, 2, -4, 3]
  
  #= calculate(:at => 3, :arr => [-7, 1, 5, 2, -4, 3, 0])
  def self.balanced?(args = {})
    raise ArgumentError unless args.has_key?(:at) and args.has_key?(:arr)
    left_sum, right_sum = 0, 0
    (0..(args[:at]-1)).each { |n| left_sum += args[:arr][n] }
    ((args[:at]+1)..(args[:arr].size-1)).each { |n| right_sum += args[:arr][n] }
    left_sum.eql?(right_sum)
  end
  
  def self.evaluate(arr)
    k = 0
    success = []
    while k < arr.size
      success << k if balanced?(:at => k, :arr => arr)
      k += 1
    end
    return success
  end
  
  
  def self.equi(arr)
    return -1 if arr.empty? or !arr.is_a?(Array)
    results = evaluate(arr)
    return -1 if results.empty?
    return results.size.eql?(1) ? results[0] : results
  end
  
  
  
  
end