Proximity Alert System

You are building a proximity alert system for a naval radar. As vessels are detected, their distance from the shore (as an integer) is recorded in a Binary Search Tree to maintain sorted order efficiently. For every new vessel detected, you must report the distance to its nearest neighbor already in the system. If it is the first vessel, report -1. Input: A single line of space-separated integers representing the order of vessel detections. Output: A single line of space-separated integers representing the proximity to the closest existing vessel for each detection. Example: Input: 50 30 80 35 Output: -1 20 30 5 Explanation: - 50: First node, -1. - 30: Closest to 50 is 50. Dist: 20. - 80: Closest to 50 is 50. Dist: 30. - 35: Closest to 30 is 30. Dist: 5. (Closer than 50)