Two Sum Indices

You are given an array of integers and a target integer. Your task is to find two distinct indices in the array such that the sum of the elements at those indices equals the target. If such a pair exists, print the indices (the first occurrence in the array) separated by a space; otherwise, print -1 -1.

Note: Each input test case starts with two numbers: the size of the array n and the target value, followed by n integers representing the array elements.

The solution should use an efficient algorithm, for example by using a hash map, so that it works well even for large arrays.

In mathematical notation, if the array is represented as \(a_0, a_1, \dots, a_{n-1}\), find indices \(i\) and \(j\) such that: \[ a_i + a_j = target, \quad i \neq j. \] If no such indices exist, output \(-1\) for both indices.

inputFormat

The input is read from standard input and consists of:

• The first line contains two integers: n (the number of elements in the array) and target.
• The second line contains n space-separated integers which are the elements of the array.

outputFormat

Print a single line containing two space-separated integers. These integers are the indices of the two numbers in the array that add up to the target. If no such pair exists, print -1 -1.

4 9
2 7 11 15

0 1