Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	QUALITY	USERS	ACC %	DIFFICULTY C I
3108	Charlesbert and Merangelou		75	44.44
3166	Permutation Exponentiation		36	14.93
3197	Tree Construction		64	20.10
3208	Yet Another Longest Palindrome Problem		69	14.04
3254	Guard		15	43.24
3305	Roman Patrollers		53	59.35
3307	Hex Tile Equations	1	37	42.34
3309	Bulletin Board		24	22.07
3347	Cestarine		64	29.10
3359	Stack		50	16.63
3360	Digital Image Recognition		28	20.48
3372	Round Table	1	61	43.81
3373	Permutation Code		43	56.10
3393	Knot or Not		10	16.67
3406	Bases		72	20.81
3412	Higgs Boson		52	19.09
3420	Falling Ice		7	12.50
3461	Song Contest		16	15.74
3462	The Skatepark´s New Ramps		11	12.26
3463	Robintron		8	22.06
3465	Drive through MegaCity		24	20.97
3466	Another Longest Common Subsequence Problem		6	5.66
3482	Alias		7	31.82
3483	Begin		4	7.94
3485	Disputes	1	86	63.75
3486	Elimination		75	30.31
3490	Hidden Triangle		12	26.87
3495	The Nobel Thief		14	51.52
3533	Game on board		26	31.14
3543	Matrica		56	39.90
3582	Restaurant Tab		24	21.90
3640	Hanoi Subway System Construction		36	40.78
3641	Earthquakes		26	36.14
3642	Pretty Printing		40	22.01
3645	Farthest Headquarters		60	26.80
3646	Adventure Tourism		46	14.43
3647	Moebius		2	2.36
3678	Cattle Bruisers		91	26.33
3679	Moo University - Emergency Pizza Order	-1	37	27.40
3725	Taming a T-REX	1	151	44.34	34
3733	Trezor		105	52.34
3762	Bread Tree		163	13.66
3867	Who is The Boss		170	25.29
3876	Tablica	1	206	58.65
3884	When (You Believe)		24	9.17
3890	Rectangles Counting		175	33.61
3893	Space settlement		67	31.56
3894	Bouncing Balls		28	31.54
3895	Matrix Game		26	21.77
3898	Even Palindrome	-1	251	10.23