"""

 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.

 Example:

 Input: s = 7, nums = [2,3,1,2,4,3]

 Output: 2

 Explanation: the subarray [4,3] has the minimal length under the problem constraint.

 """

 """

 滑动窗口，与leetcode713类似

 """

 class Solution:

     def minSubArrayLen(self, s: int, nums):

         _sum = 0

         res = len(nums) + 1

         i = 0

         for j in range(len(nums)):

             _sum += nums[j]

             while _sum >= s: #！！！

                 res = min(res, j-i+1)

                 _sum -= nums[i]

                 i += 1

         return res if res <= len(nums) else 0