Minimum Size Subarray Sum

public int minSubArrayLen(int[] nums, int s) {
    if(nums==null||nums.length==0) return 0;
    int i=0,j=0;
    int sum=0, int ret=Integer.MAX_VALUE;
    while(j<nums.length){
        sum+=nums[j++];
        while(sum>=s){
            ret=Math.min(ret,j-i);
            sum-=nums[i++];
        }
    }
    return ret == Integer.MAX_VALUE ? 0 : ret;
}