Two Sum Problem

You are given an array of integers and a target integer. Your task is to find two distinct indices i and j (0-indexed) such that

[ a_i + a_j = target ]

If such a pair exists, output the two indices; otherwise, output None. It is guaranteed that each input has at most one solution.

inputFormat

The input is given via standard input in the following format:

• Line 1: An integer n, representing the number of elements in the array.
• Line 2: n space-separated integers representing the array elements.
• Line 3: An integer representing the target sum.

outputFormat

If a valid pair is found, output two integers (the indices) separated by a space. If no such pair exists, output None.

4
2 7 11 15
9

0 1