Identify the Orchestrator in a Server Connection Graph

## Problem An undirected connection list describes one orchestrator server and its workers. Every connection contains the orchestrator as one endpoint; workers never connect directly to one another. Return the orchestrator ID. ### Function Contract Implement `findOrchestrator(connections)`, where each connection is a two-element string array. Return a string. ### Constraints & Assumptions - `2 <= len(connections) <= 200,000`. - Each connection joins two distinct nonempty server IDs. - Exactly one server ID appears in every connection. - Duplicate connection pairs do not appear. - Connection direction is irrelevant. ### Clarifying Questions to Ask - Are the pairs directed? No. - Can a worker connect to another worker? No. - Is the orchestrator guaranteed to be unique? Yes. - Must every worker have exactly one listed connection? The guarantee that every edge touches the orchestrator is sufficient; a worker appears on only its orchestrator edge in valid input. ```hint The first pair leaves only two candidates The orchestrator must be one endpoint of the first connection. Use a later connection to eliminate the endpoint that is absent. ``` ### Example `[["O", "A"], ["O", "B"], ["C", "O"]]` returns `"O"`. `[["worker-1", "root"], ["worker-2", "root"]]` returns `"root"`. ### Evaluation Focus - Treats pairs as undirected and uses the common-endpoint guarantee. - Does not build a general graph traversal for a star-center problem. - Runs in `O(m)` time and `O(1)` auxiliary space beyond string references. ### Extensions to Discuss 1. How would you validate the promise that workers never connect? 2. What if a small number of malformed worker-to-worker edges may be present? 3. How would directed heartbeats change the identification rule?