Earliest Time When All People Become Connected

Given n people labeled from 0 to n - 1 and a list of friendship logs, where logs[i] = [timestamp, x, y] means that people x and y became friends at timestamp. Friendship is transitive: if a is connected to b and b is connected to c, then all three people belong to the same friend group. Return the earliest timestamp at which all n people are connected in one group. Return -1 if this never happens. Input Format n m timestamp_1 x_1 y_1 timestamp_2 x_2 y_2 ... timestamp_m x_m y_m The logs are not necessarily sorted by timestamp. Output Format Print the earliest timestamp when everyone becomes connected, or -1 if they never do. Example 1 Input: 6 8 20190101 0 1 20190104 3 4 20190107 2 3 20190211 1 5 20190224 2 4 20190301 0 3 20190312 1 2 20190322 4 5 Output: 20190301 Constraints 2 <= n <= 100 1 <= m <= 10^4 0 <= x, y < n, x != y Example Input 6 8 20190101 0 1 20190104 3 4 20190107 2 3 20190211 1 5 20190224 2 4 20190301 0 3 20190312 1 2 20190322 4 5 Output 20190301