Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
8317	Red Balls	46	44.54
8318	color the balls	68	43.89	50 50
8320	Spreadsheet scrolling	77	29.39
8321	Chocolate distribution	115	23.85
8323	Triangle equality	60	35.50
8325	Partitioning the plane	39	41.10
8326	Leaky containers	32	40.20
8327	Progressive progressions	56	60.45
8328	Move the books	27	24.19
8331	Sister cities	39	50.50
8332	Ski slopes	28	22.08
8333	Place-name game	73	35.94
8421	Fun With Inequalities	141	37.74	17 17
8423	Recover Polynomials	57	49.36
8427	Permutation Game	34	39.81
8428	Grid Tiling	24	22.56
8429	Array Sorting	67	17.26
8461	Adventure in Moving	44	28.43	17 17
8478	Ancient Pocket Calculator	7	4.32
8542	Modern Pocket Calculator	35	9.11	28 6
8546	Manoj and Pankaj	51	19.28
8593	Covering the Corral	9	32.50
8594	Tails all the way	291	34.51
8627	I2C	32	24.68
8628	Selling Land	73	48.35
8657	The Bovine Accordion and Banjo Orchestra	7	21.43
8661	Bogosort	45	15.07
8663	Squares Game	34	39.00
8816	Mravograd	28	28.79	17 34
8836	Yet Another Sequence Problem	76	23.29
8844	Detection of Extraterrestrial	124	36.22
8846	Fudan Extracurricular Lives	7	25.00
8848	Herbicide	18	18.10
8849	Imitation	28	24.46
8886	Guess number!	20	5.65	34 34
8945	Grid points (speed variation)	29	23.71
8951	brownie	72	48.89
8971	LQDNUMBERS	35	34.56
8992	A los saltos	38	28.57
9000	Bob and his new kite factory	2	1.20
9030	Bob and his towers	38	29.19
9038	Chessboard Billiard	52	25.83
9063	Shuffling cards	16	30.38
9084	Journey to Mars	104	23.49
9086	Formula 3D	6	10.94
9118	Genetic Fraud	151	29.56
9121	Magical Crafting	57	47.13
9123	Security Zone	38	27.25
9124	Sightseeing	118	17.75
9125	Suiting Weavers	87	29.21