ciag = [1,2,-5,7]
sums = []
i = 0
zakres = 1

loop do
  break if zakres > ciag.size-1

  if i + zakres > ciag.size
    zakres += 1
    i = 0
  end

  sum = 0

  for j in i..i+zakres-1
    sum += ciag[j].to_i
  end
  sums << sum
  i += 1
end

puts sums.inspect
## Output
[1, 2, -5, 7, 3, -3, 2, -2, 4, 5]