Find the pairs of elements in an array

Given an array of $N$ integers, and an integer $K$, find pairs of integers in the array whose sum is equal to $K$. If there are no pairs,output should be {}. ### Input - The first line of input will contain a single integer $T$, denoting the number of test cases. - Each test case consists of multiple lines of input. - The first line contains the number of elements $N$. - The second line o