FirstsChallengeFirst solve
19:05:00000:00:00
19:07:51100:02:51
19:09:18200:04:18
19:10:12300:05:12
19:15:14400:10:14
19:15:37500:10:37
19:19:23600:14:23
19:21:51700:16:51
19:25:11900:20:11
19:26:321000:21:32
19:27:431100:22:43
19:31:361200:26:36
19:41:481300:36:48
20:09:071401:04:07
20:19:241501:14:24
21:11:271602:06:27

Note that this is global, somebody can solve a problem first and be the last to solve the next.