Sphere Online Judge (SPOJ)

list of classical problems (unsolved)

ID	NAME	USERS	ACC %	DIFFICULTY C I
7490	Biology	14	5.93
7556	B - Stock Charts	45	40.48
7558	D - Alphabetomials	14	41.46
7559	E - Football Team	9	12.50
7560	F - Interesting Ranges	13	21.33
7563	Hi6	39	16.55	26 26
7566	Expected Cycle Sums	52	47.89
7579	Power Calculus	326	49.33	34 17
7581	The Best Name for Your Baby	13	33.33
7589	Cave Crisis	13	54.84
7599	Optimal Strategy for the ICPC	10	21.15
7627	Driving Direction	14	49.02
7629	Building Ports	45	12.44
7630	SHOPPERS	150	36.75
7632	Architecture	20	24.24
7666	Telecommunications	26	28.30
7680	Electrical Engineering	17	33.97
7692	Chemistry	72	13.88
7693	Environmental Engineering	38	39.23
7737	Escape	57	34.36
7740	Fence	23	25.49
7745	Bingo!	758	38.89	17 1
7746	Cocircular Points	64	16.93	42 17
7758	Growing Strings	176	32.39
7763	Ingenious Metro	84	66.84
7772	Help a researcher	62	48.95
7777	National Treasure	35	31.50
7779	Stock Chase	76	30.19	17 17
7783	Commuting Functions	49	25.94
7807	The Lucky Prisoner	27	9.84
7857	Tower Game (Hard)	62	14.63	34 34
7862	Prisoner of Benda	27	25.83
7874	Calculator	29	24.36
7884	Crni	60	55.93
7886	Boards (Hard)	40	37.14
7891	Fibonacci Sequence	102	30.56	34 34
7960	Multiplicative Palindrome	34	27.78
7972	World of cubes	37	16.88
8055	Playground	280	25.94
8062	Shopping Rush	73	63.26
8097	Islands	73	46.82
8104	Friendly Knights	151	45.76
8108	POLYU	36	26.76
8189	Circles On A Screen	83	28.67
8282	Distance	52	23.74
8286	Perfect Matching	92	19.19	1 17
8316	Win gold medal	55	26.03
8317	Red Balls	47	44.77
8318	color the balls	69	42.80	50 50
8320	Spreadsheet scrolling	78	29.61