public int maxSubArray_Divie_and_conquer_helper(int[] nums, int left, int right) {
        if (left == right)
            return nums[left];
        int mid = (right - left) / 2 + left;
        return Math.max(Math.max(maxSubArray_Divie_and_conquer_helper(nums, left, mid), maxSubArray_Divie_and_conquer_helper(nums, mid + 1, right)),
                hepler(nums, left, mid, right));
    }