Code Challenge of the Day: Minimal length subarray >= target (hard)

Return the length of the shortest contiguous subarray with sum >= target, or 0 if none.
Write min_subarray_len(nums, target).

Starter:

def min_subarray_len(nums, target):
    # TODO
    pass

---

Solve it interactively in your browser (no setup), check your answer instantly, and keep your daily streak going on IWTLP: https://iwtlp.com/challenge