Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
3314	Umnozak	102	29.03	42 17
3347	Cestarine	59	34.58
3359	Stack	45	15.60
3360	Digital Image Recognition	25	8.19
3373	Permutation Code	41	55.70
3393	Knot or Not	6	13.56
3406	Bases	68	21.12
3412	Higgs Boson	48	18.93
3414	Bora Bora	144	48.65	34 26
3415	Shrinking Polygons	230	18.87
3420	Falling Ice	7	24.14
3461	Song Contest	12	14.44
3462	The Skatepark´s New Ramps	10	32.65
3463	Robintron	6	22.22
3465	Drive through MegaCity	23	25.16
3466	Another Longest Common Subsequence Problem	6	42.86
3482	Alias	4	57.14
3483	Begin	4	11.11
3485	Disputes	80	62.59
3486	Elimination	67	28.57
3490	Hidden Triangle	9	28.85
3495	The Nobel Thief	6	38.10
3533	Game on board	28	36.73
3543	Matrica	52	39.06
3582	Restaurant Tab	24	27.27
3640	Hanoi Subway System Construction	32	41.75
3641	Earthquakes	23	37.68
3642	Pretty Printing	39	24.38
3645	Farthest Headquarters	55	25.80
3646	Adventure Tourism	44	17.28
3647	Moebius	1	2.67
3678	Cattle Bruisers	86	25.65
3733	Trezor	99	52.09
3762	Bread Tree	161	13.50
3867	Who is The Boss	161	24.47
3872	Party At School	49	24.38
3884	When (You Believe)	23	8.98
3890	Rectangles Counting	173	33.28
3893	Space settlement	64	43.31
3894	Bouncing Balls	27	37.74
3895	Matrix Game	25	31.71
3900	MinCut Query	77	28.78
3901	Black and White Nim	55	44.50
3922	Mystical River	127	25.47
3926	Manhattan Wire	81	14.32
3927	Polygon on the Grid	22	36.62
3929	Different Digits	71	22.60
3930	Group Partition	67	29.94
3935	SHIFT Operator on Matrix	187	42.04
3939	Search of Concatenated Strings	27	26.32