Two Sum Challenge

Given an array of integers and a target integer, your task is to find two distinct indices such that the numbers at these indices add up to the target value.

If such a pair exists, output the two indices (0-indexed) separated by a space. In case there are multiple valid answers, output the first found pair (i.e., the pair corresponding to the smallest second index). If no such pair exists, output [].

Note: The solution must run in linear time using an appropriate data structure.

The underlying algorithm can be expressed by the equation:

\(a_i + a_j = target\), where \(i \neq j\) and \(0 \leq i,j < n\).

inputFormat

The input consists of two lines:

• The first line contains two integers n and target, where n is the number of elements in the array.
• The second line contains n space-separated integers representing the elements of the array.

outputFormat

If a valid pair exists, output the two 0-indexed positions separated by a space. If no such pair exists, output [].

4 9
2 7 11 15

0 1