Tape equilibrium (Codility exercise)

tape_equilibrium.rb

def solution(a)
  minor = 1/0.0

  left = 0
  right = a.reduce(:+)

  a[0..-2].each do |x|
    left  += x
    right -= x

    abs = (left - right).abs

    minor = abs if abs < minor
  end

  minor
end