Medium
Given an array of positive integers nums and a positive integer target, return the minimal length of a contiguous subarray whose sum is ≥ target. If there is none, return 0.
Input: target = 7, nums = [2,3,1,2,4,3] Output: 2 Explanation: The subarray [4,3] has sum 7 and length 2.
Input: target = 11, nums = [1,1,1,1,1] Output: 0