Its a personal choice I guess. I would rather try to avoid that - for two reasons

To use that time for refreshing concepts
To prevent getting myself exausted or depressed ( in worst case if I find some very hard problems ).

Its best to go there with fresh mind and with lot of enrgy

I wouldn't - if you do poorly that can't be good mentally going into the real thing, and you might just make yourself tired, too. It seems like you have a lot more to lose (stamina, confidence) than to gain (you're not really learning unless you take the extra time to work on your mistakes). Maybe 2 days before so you can use the last day to practice what you did wrong, but the day before seems like a high risk, low reward proposition.