Two Sum II - Input Array Is Sorted

Given a **1-indexed** array of integers `numbers` that is already **_sorted in non-decreasing order_**, find two numbers such that they add up to a specific `target` number. Let these two numbers be `numbers[index1]` and `numbers[index2]` where `1 <= index1 < index2 <= numbers.length`. Return_ the indices of the two numbers, _`index1`_ and _`index2`_, **added by one** as an integer array _`[index1, index2]`_ of length 2._ The tests are generated such that there is **exactly one solution**. You **may not** use the same element twice. Your solution must use only constant extra space.   **Example 1:** **Input:** numbers = [2,7,11,15], target = 9 **Output:** [1,2] **Explanation:** The sum of 2 and 7 is 9. Therefore, index1 = 1, index2 = 2. We return [1, 2]. ``` **Example 2:** **Input:** numbers = [2,3,4], target = 6 **Output:** [1,3] **Explanation:** The sum of 2 and 4 is 6. Therefore index1 = 1, index2 = 3. We return [1, 3]. ``` **Example 3:** **Input:** numbers = [-1,0], target = -1 **Output:** [1,2] **Explanation:** The sum of -1 and 0 is -1. Therefore index1 = 1, index2 = 2. We return [1, 2]. ```   **Constraints:** - `2 <= numbers.length <= 3 * 104` - `-1000 <= numbers[i] <= 1000` - `numbers` is sorted in **non-decreasing order**. - `-1000 <= target <= 1000` - The tests are generated such that there is **exactly one solution**.