https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/

Again, a straightforward question. If you are not using the fact that the numbers are sorted – you are doing it wrong.

With 2 sum, since the numbers were not sorted, we had to use a Dictionary/Map to get the optimal solution.

But since the numbers are sorted in this question, we could use two pointers (left and right), to get a O(n) space and O(1) time solution.