Find all pairs of integers within an array which sum to a specified value

Question

Design an algorithm to find all pairs of integers within an array which sum to a specified value.

I have tried this problem using a hash

Answer 1

Assume required sum = R

1. sort the array
2. for each number in the array A(n), do a binary search to find the number A(x) such that A(n) + A(x) = R