checking if 2 numbers of array add up to I

Question

I saw a interview question as follows: Give an unsorted array of integers A and and an integer I, find out if any two members of A add up to I.

any clues?

ti

Answer 1

This might be possible in the following way: Before putting the elements into the hashmap, you can check if the element is greater than the required sum. If it is, you can simply skip that element, else you can proceed with putting it into the hashmap. Its a slight improvement on your algorithm, although the overall time still remains the same.