Pair Sum Problem Statement

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.

Note:

Each pair should be ordered such that the first value is less than or equal to the second value. The list of pairs should be sorted in non-decreasing order based on their first values. If two pairs have the same first value, the pair with the smaller second value should come first.

Input:

N S ARR[0] ARR[1] ... ARR[N-1]

Output:

C x1 y1 x2 y2 ...

Example:

Input:

N = 5, S = 7 ARR = [3, 1, 2, 4, 5]

Output:

[2, 5] [3, 4]

Constraints:

1 ≤ N ≤ 10³

-10⁵ ≤ ARR[i] ≤ 10⁵

-2 * 10⁵ ≤ S ≤ 2 * 10⁵

Time Limit: 1 sec

Note:

You don't need to print the output; just implement the logic to return the required result.

Question

Pair Sum Problem Statement

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.

Note:

Each pair should be ordered such that the first value is less than or equal to the second value. The list of pairs should be sorted in non-decreasing order based on their first values. If two pairs have the same first value, the pair with the smaller second value should come first.

Input:

N S
ARR[0] ARR[1] ... ARR[N-1]

Output:

C
x1 y1
x2 y2
...

Example:

Input:

N = 5, S = 7
ARR = [3, 1, 2, 4, 5]

Output:

[2, 5]
[3, 4]

Constraints:

1 ≤ N ≤ 10³
-10⁵ ≤ ARR[i] ≤ 10⁵
-2 * 10⁵ ≤ S ≤ 2 * 10⁵

Time Limit: 1 sec

Note:

You don't need to print the output; just implement the logic to return the required result.

Accepted Answer

Given an array and a target sum, find all pairs of elements in the array that add up to the target sum.

Create an empty list to store the pairs
Iterate through the array and for each element, check if there is a complement (target sum minus the current element) in the array
If a complement is found, add the pair (current element, complement) to the list
Sort the list of pairs in non-decreasing order of their first value
If two pairs have the same first value, sort them based on the second value
Return the list of pairs