leetcode209. Minimum length subarray

Address ：https://leetcode.cn/problems/minimum-size-subarray-sum/
describe ： 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 [$num{s}_l$, $num{s}_{l+1}$, …, $num{s}_{r-1}$, $num{s}_r$] , 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 [4,3] Is the smallest subarray in this condition .

example 2：

Input ：target = 4, nums = [1,4,4]
Output ：1

example 3：

Input ：target = 11, nums = [1,1,1,1,1,1,1,1]
Output ：0

Ideas ： The sliding window
answer ：

class Solution {
    
    public int minSubArrayLen(int target, int[] nums) {
    
        int len = nums.length;
        int left = 0;
        int sum = 0;
        int res = Integer.MAX_VALUE;

        for (int right = 0; right < len; right++) {
    
            sum += nums[right];
            while (sum >= target) {
    
                res = Math.min(res, right - left + 1);
                sum -= nums[left++];
            }
        }

        return res == Integer.MAX_VALUE ? 0 : res;
    }
}