Problems from Waterloo Programming Contest 2009-06-13

	Submissions				Users
Name	Total	Acc.	Ratio	Fastest	Total	Acc.	Ratio	Difficulty
Convex Hull	811	187	23%	0.03	148	110	74%	7.1
Fire!	2171	502	23%	0.01	379	291	77%	5.4
Nice Prefixes	55	13	24%	0.02	17	10	59%	8.2
Slalom 2	182	64	35%	0.10	51	46	90%	5.2
Tic Tac Toe	646	44	7%	0.01	78	32	41%	8.3