# Earliest Time of Full Connectivity Implement `earliest_full_connection(n: int, events: list[list[int]]) -> int`. There are `n` entities labeled `0` through `n - 1`. Each event is `[timestamp, a, b]` and creates a permanent undirected connection between entities `a` and `b`. Events may be given in any order. Return the earliest timestamp at which all entities are connected through direct or indirect connections. ### Input Domain - `1 <= n <= 200,000`. - `0 <= len(events) <= 300,000`. - Timestamps fit in signed 64-bit integers. - Every endpoint is a valid entity label; self-connections and repeated connections may occur. ### Output Rules - All events with the same timestamp take effect as one time group. - Return the timestamp of the first group after which there is exactly one connected component. - Return `0` when `n = 1`, even if there are no events. - Return `-1` if full connectivity never occurs. ### Constraints - Ordering among events with equal timestamps must not change the answer. - Target time is `O(m log m + m alpha(n))` for `m` events. ### Examples #### Example 1 Input: `n = 4, events = [[5,0,1],[2,2,3],[7,1,2]]` Output: `7` #### Example 2 Input: `n = 3, events = [[4,0,1],[4,1,0]]` Output: `-1` ```hint Track component count After sorting by timestamp, a successful union reduces the number of connected components; full connectivity occurs when that count reaches one. ```