Leetcode 209. subarray with the smallest length

Given a containing n An array of positive integers and a positive integer target .

Find the sum of the array ≥ target The smallest length of Continuous subarray [numsl, numsl+1, …, numsr-1, numsr] , And return its length . If there is no sub array that meets the conditions , return 0 .

Example 1：

 Input ：target = 7, nums = [2,3,1,2,4,3]
 Output ：2
 explain ： Subarray  [<