F maxsumseq(sequence)
   V (start, end, sum_start) = (-1, -1, -1)
   V (maxsum_, sum_) = (0, 0)
   L(x) sequence
      sum_ += x
      I maxsum_ < sum_
         maxsum_ = sum_
         (start, end) = (sum_start, L.index)
      E I sum_ < 0
         sum_ = 0
         sum_start = L.index
   assert(maxsum_ == sum(sequence[start + 1 .. end]))
   R sequence[start + 1 .. end]

print(maxsumseq([-1, 2, -1]))
print(maxsumseq([-1, 2, -1, 3, -1]))
print(maxsumseq([-1, 1, 2, -5, -6]))
print(maxsumseq([-1, -2, 3, 5, 6, -2, -1, 4, -4, 2, -1]))