Given an integer array, output all pairs that sum up to a specific value 𝑘. Consider the fact that the same number can add up to 𝑘 with its duplicates in the array.
For example the array is [1, 1, 2, 3, 4] and the desired sum is 4. Should we
output the pair (1, 3) twice or just once? Also do we output the reverse of a
pair, meaning both (3, 1) and (1, 3)? Let’s keep the output as short as
possible and print each pair only once. So, we will output only one copy of
(1, 3). Also note that we shouldn’t output (2, 2) because it’s not a pair of
two distinct elements.
Your program receives a comma separated list of integers where the first value is the desired sum 𝑘 and all others are the integers to search for pairs in. Your output should be a list of comma separated pairs where the lower of the two numbers is always on the left side:
ƒ(10, [3, 4, 5, 6, 7]) -> [(4, 6), (3, 7)]
ƒ( 8, [3, 4, 5, 4, 4]) -> [(3, 5)]