Exercise: Shortest sublist with sum over limit



    >>> shortest([], 7)
    -1
    >>> shortest([2, 3], 7)
    -1
    >>> shortest([2, 3], 0)
    0
    >>> shortest([], 0)
    0
    >>> shortest([7, 3], 7)
    1
    >>> shortest([4, 7, 3], 7)
    1
    >>> shortest([1, 23, 1, 1, 10, 11, 12], 30)
    3
    >>> shortest([1, 23, 1, 1, 10, 11, 12], 24)
    2
    >>> shortest([1, 10, 11, 40], 30)
    1