Question 1 2 Sum Sorted

class Solution {
    public int[] twoSum(int[] numbers, int target) {
        // sanity check
        if (numbers == null) {
            return new int[]{-1, -1};
        }
        int left = 0;
        int right = numbers.length - 1;
        while (left < right) {
            int sum = numbers[left] + numbers[right];
            if (sum == target) {
                return new int[]{left + 1, right + 1};
            }
            else if (sum < target) {
                left++;
            }
            else {
                right--;
            }
        }
        return new int[]{-1, -1};
    }
}