Two Sum Problem

Given an array of integers and a target integer \(T\), find two distinct indices \(i\) and \(j\) such that the sum of the numbers at these indices equals \(T\), i.e., \(nums[i] + nums[j] = T\). If such a pair exists, output the two indices separated by a space. Otherwise, output [].

The input is read from standard input and the output should be written to standard output. The problem guarantees that if a solution exists, the returned indices are unique. Note that the order of the indices should correspond to the order of discovery in a single pass using a hash map.

Examples:

• For the input array [2, 7, 11, 15] and target 9, the correct output is 0 1 because 2 + 7 = 9.
• For the input array [1, 2, 3, 4, 5] and target 10, no such pair exists and the correct output is [].

inputFormat

The input consists of three lines:

1. The first line contains an integer \(n\), which is the number of elements in the array.
2. The second line contains \(n\) space-separated integers representing the array elements.
3. The third line contains an integer representing the target sum \(T\).

outputFormat

If a valid pair exists, output the two indices separated by a space. If no such pair exists, output [] (without quotes).

4
2 7 11 15
9

0 1