# SESO09 - Editorial

### Problem Explanation

The task is to find all pairs of integers from a list of `n` pairs where the sum of the elements in each pair is divisible by a given integer `k`. The order of pairs in the output should match the order in which they were provided in the input.

### Approach

To find and print all pairs of integers from a list where the sum of each pair is divisible by a given integer `k`, we first read the number of pairs `n` and the integer `k`, then store the pairs in a vector. We iterate through each pair, calculate the sum of the two integers, and check if the sum is divisible by `k`. If it is, we print the pair, ensuring that the output order matches the input order. This approach efficiently processes each pair in O(n) time.

### Complexity Analysis

• Time Complexity: The time complexity is O(n), where `n` is the number of pairs. This is because the program iterates through each pair once to check if the sum is divisible by `k`.

• Space Complexity: The space complexity is O(n) due to the storage of the pairs in a vector, or if O(1) if we donâ€™t consider the input storage space.