Start time, duration and extra time
When a participant may work, and for how long, comes from three places: the contest's schedule, its duration in virtual mode, and the extra time granted to one participant. The schedule is on Settings → General; extra time is on the participant's own page.
Schedule
Settings → General → Schedule opens a dialog with the contest's start time and end time. Times are shown in your own timezone, which you set in your account settings; participants see the same moment in theirs.
In online mode that window is the contest — everyone works in it and the clock is the same for everybody. In virtual mode it is the period during which participants may begin.
Changing the schedule of a contest that has not started moves it. Note that the Start action in the contest header does not respect the schedule at all: it rewrites the start time to now and shifts the end to preserve the length. See Open, freeze, suspend and close a contest.
The schedule is locked once the contest is finalized.
Duration
Duration applies to virtual contests only, and is the number of minutes one participant gets once they press Start. Their window closes after that many minutes or at the contest's end time, whichever comes first — a four-hour duration inside a window that ends at 18:00 gives a participant who starts at 16:00 two hours, not four.
Online contests have no duration field. The window is the duration.
Plans cap the longest contest that can be created; a contest longer than the cap is refused.
Per-participant times
Every participant record carries the moment they started and the moment they will finish, and the finish time already includes any extra time granted to them. Both are shown in the header of the participant's page.
Extra time
Extra time is set per participant, on the participant page, as a number of minutes. It extends that one participant's end time and nobody else's — the tool for a competitor who lost twenty minutes to a broken machine.
It is disabled for official participants once the contest is finalized.
Finishing early and pausing
Two toggles on Settings → Participation hand time control to the participant:
Allow to finish early gives them a Finish button that ends their participation before the clock runs out. It is final; there is no way for them to resume afterwards.
Allow to pause gives them a Pause button, which hides the contest interface until they start again. It is meant for onsite contests, where a participant steps away from the machine. A pause is voluntary, and is a different thing from an organizer withdrawing access.
Taking part after the end
Two more toggles on the same card extend a contest past its end time. They answer different questions and can be used together.
Allow follow up lets people who never took part join once the contest is over, and work through it virtually and unofficially. Their results do not enter the official standings.
Allow upsolve lets people who did take part carry on solving after their own time ends. Upsolve submissions are graded and recorded separately from the contest-time score, and appear on the Upsolve view of the scoreboard. Upsolving needs a plan that allows contests to stay open for it; if the toggle isn't there, see Why a section is missing. Note that a contest left open for upsolving still counts against the plan's active-contest quota.
Editorials, on Settings → General, is the third thing that changes after the end: with it on, the author's write-up of each problem becomes readable to a participant once their own participation is over. See Editorials.
The reminder email
Reminder notification, on Settings → General, emails registered participants one hour before the contest starts. It is a single toggle with no text of its own to write. Anything else you need to tell participants before the start belongs on an overview page or in an announcement once the contest is running.
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