Given an array of ``n`` positive integers and a positive integer s, find the minimal length of a ``contiguous`` subarray of which the ``sum ≥ s``. If there isn't one, return 0 instead.

解释：子数组 [4,3] 是该条件下的长度最小的连续子数组。 进阶： 如果你已经完成了 O(n) 时间复杂度的解法, 请尝试 O(n log n ...