Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
8189	Circles On A Screen	81	28.40
8265	Zero Count	14	12.50
8282	Distance	50	25.08
8286	Perfect Matching	90	18.98	1 17
8316	Win gold medal	55	26.67
8317	Red Balls	43	44.25
8318	color the balls	66	45.93	50 50
8320	Spreadsheet scrolling	76	32.64
8321	Chocolate distribution	115	24.51
8323	Triangle equality	58	43.85
8325	Partitioning the plane	37	39.49
8326	Leaky containers	31	41.84
8327	Progressive progressions	54	64.75
8328	Move the books	27	33.33
8331	Sister cities	36	51.65
8332	Ski slopes	24	21.90
8333	Place-name game	71	37.29
8421	Fun With Inequalities	141	37.81	17 17
8423	Recover Polynomials	52	48.30
8427	Permutation Game	32	41.05
8428	Grid Tiling	23	22.93
8429	Array Sorting	64	16.60
8461	Adventure in Moving	43	27.98
8478	Ancient Pocket Calculator	7	4.44
8542	Modern Pocket Calculator	35	9.12	28 6
8546	Manoj and Pankaj	51	23.05
8593	Covering the Corral	8	31.58
8594	Tails all the way	287	34.27
8627	I2C	32	25.79
8628	Selling Land	72	47.49
8657	The Bovine Accordion and Banjo Orchestra	6	25.00
8661	Bogosort	42	14.33
8663	Squares Game	34	48.75
8666	Maximum - Profit -- Version II	92	43.40	1 1
8816	Mravograd	29	32.00	17 34
8836	Yet Another Sequence Problem	75	23.75
8844	Detection of Extraterrestrial	118	36.28
8846	Fudan Extracurricular Lives	7	25.00
8848	Herbicide	18	41.56
8849	Imitation	23	36.25
8886	Guess number!	17	5.03	34 34
8945	Grid points (speed variation)	24	24.68
8951	brownie	62	49.06
8971	LQDNUMBERS	31	36.44
8992	A los saltos	36	30.41
9000	Bob and his new kite factory	2	1.42
9030	Bob and his towers	38	31.76
9038	Chessboard Billiard	47	26.09
9063	Shuffling cards	17	31.65
9084	Journey to Mars	98	23.76