Given an array ofnpositive integers and a positive integers, find the minimal length of acontiguoussubarray of which the sum ≥s. If there isn't one, return 0 instead.

For example, given the array[2,3,1,2,4,3]ands = 7,
the subarray[4,3]has the minimal length under the problem constraint.

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tag: Two Pointers

class Solution {
    public int minSubArrayLen(int s, int[] nums) {
        if (nums == null || nums.length == 0) return 0;

        int sum = 0, j = 0;
        int ans = Integer.MAX_VALUE;
        for (int i = 0; i < nums.length; i++){
            while (j < nums.length && sum < s){
                sum += nums[j++];
            }

            if (sum >= s){
                ans = Math.min(ans, j - i);        
            }

            sum -= nums[i];
        }

        if (ans < Integer.MAX_VALUE){
            return ans;
        }
        else{
            return 0;
        }
    }
}