Parse and group log lines by thread id, then sort by timestamp

Problem You are given N log lines (strings). Each line follows the format: <timestamp> <thread_id> <level> <message> timestamp: an ISO-8601 time string, e.g. 2024-01-01T10:00:00Z thread_id: a no-space identifier, e.g. t1, thread-007 level: a no-space token such as INFO, WARN, ERROR message: the rest of the line (may contain spaces) Group logs by thread_id, and within each group sort the log lines by timestamp in ascending order. Output For each thread_id: print the thread_id on its own line then print all original log lines for that thread (unchanged), sorted by timestamp ascending Thread groups must be printed in ascending lexicographic order of thread_id. Input (stdin) Line 1: integer N Next N lines: one log line each Constraints 1 <= N <= 2 * 10^5 each line length <= 500 timestamps are valid and can be compared lexicographically to reflect chronological order. Example Input: 5 2024-01-01T10:00:02Z t1 INFO start 2024-01-01T10:00:01Z t2 WARN w1 2024-01-01T10:00:03Z t1 INFO end 2024-01-01T10:00:00Z t1 ERROR boom 2024-01-01T10:00:02Z t2 INFO ok Output: t1 2024-01-01T10:00:00Z t1 ERROR boom 2024-01-01T10:00:02Z t1 INFO start 2024-01-01T10:00:03Z t1 INFO end t2 2024-01-01T10:00:01Z t2 WARN w1 2024-01-01T10:00:02Z t2 INFO ok Example Input 5 2024-01-01T10:00:02Z t1 INFO start 2024-01-01T10:00:01Z t2 WARN w1 2024-01-01T10:00:03Z t1 INFO end 2024-01-01T10:00:00Z t1 ERROR boom 2024-01-01T10:00:02Z t2 INFO ok Output t1 2024-01-01T10:00:00Z t1 ERROR boom 2024-01-01T10:00:02Z t1 INFO start 2024-01-01T10:00:03Z t1 INFO end t2 2024-01-01T10:00:01Z t2 WARN w1 2024-01-01T10:00:02Z t2 INFO ok