Yes and no. All scores submitted are taken into account, but only the highest score you get during the event will count as your final leaderboard score.
That means if you score 100 points on day 1, and 200 points on day 2, then 200 points will be your leaderboard score. But, if you score 150 points on day 3, then 200 points will still be your leaderboard score.
Again: only your highest score submitted during the event will show up on the leaderboard! Any following score submissions that have a lower score will NOT replace your high score!