Problems from Waterloo Programming Contest 2009-06-13

	Submissions				Users
Name	Total	Acc.	Ratio	Fastest	Total	Acc.	Ratio	Difficulty
Convex Hull	1027	245	24%	0.03	198	147	74%	6.8
Fire!	2772	633	23%	0.01	494	383	78%	5.2
Nice Prefixes	62	15	24%	0.02	20	12	60%	8.6
Slalom 2	785	140	18%	0.10	118	84	71%	6.2
Tic Tac Toe	1197	62	5%	0.01	132	43	33%	9.0