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

Find pairs of elements in an array that sum up to a given value, sorted in a specific order.

Iterate through the array and use a hash set to store elements seen so far.
For each element, check if the complement (S - current element) is in the set.
If found, add the pair to the result list and continue.
Sort the result list based on the criteria mentioned in the problem statement.