Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
4552	Adding up Triangles	140	35.23
4558	I Speak Whales	188	42.51	17 17
4559	A Day at the Races	128	17.79
4574	Riding in cycles	44	23.96
4586	Texas Trip	70	38.84
4588	SETI	130	66.67
4657	Gas Wars	145	35.87	34 17
4717	Grid Points in a Triangle	99	46.63
4785	Starship	16	31.25
4828	ZSequence	53	18.02
4881	Words on graphs	108	11.94	34
5011	Library for Madrid	59	42.62	17 17
5014	Crazy Receptionist	11	11.11
5015	Decode the Castanets	36	40.68
5016	Guernica	26	61.54
5018	Street Gambler	31	47.83
5102	Mystic Craft	57	46.20
5103	Top 10	43	15.98
5104	Spam Detection	16	15.97
5115	Two "Ways"	67	15.62
5143	Binary Integer	53	50.00
5144	Cryptography Reloaded (Act I)	34	26.43
5145	Déjà vu	17	14.94
5146	Experiment on a … Cable	16	36.36
5147	Fire-Control System	37	22.40	34 17
5149	History of Languages	32	17.70
5150	Junk-Mail Filter	147	22.57
5153	Compressed String	46	28.21
5154	Cryptography Reloaded (Act II)	36	27.49
5155	Exciting Time	45	13.96
5156	Flowers Placement	43	31.33
5158	Heroes Arrangement	17	12.94
5159	Island Explorer	37	15.74
5160	Jinyuetuan Puzzle	45	37.70
5163	Tower of Vientiane	105	34.94
5182	Double Sorting	15	8.70
5300	Mexican Standoff	26	24.19
5373	Four Mines	14	6.25
5446	Fishing Net	176	31.96
5462	Art Plagiarism	13	21.84
5522	Buy Your House	17	39.62
5523	Highway Patrol	19	43.01
5531	Kutevi Hard	90	43.40
5566	Math with Bases	15	10.78
5637	LL and ErBao	5	41.43
5831	Permutation Jumping	137	59.48
5973	Selecting Teams	235	23.33
6052	PBCGAME	85	27.45
6059	Another GCD problem	342	45.16
6072	Chocolate	161	21.61	17 34