Two Sum

Given a list of integers and a target, find the two positions whose values add up to the target.

Input:

• Line 1: n, the number of values.
• Line 2: n integers.
• Line 3: the target.

Output: the two zero-based indices i j with i < j, separated by a space. Exactly one such pair exists.

2 <= n <= 1000, values and target between -10^9 and 10^9. Each input has exactly one valid pair, and the same position cannot be used twice.