Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
2273	Ferries	30	18.28
2275	Toil for Oil	13	30.54
2318	Overlapping Words	87	22.38
2319	Sequence	218	28.10
2323	Broken Compass	43	13.46
2325	String Distance	213	21.42
2413	Building Beacons	41	22.68
2417	Eliminate The Enemies	22	20.98
2418	Flying Frogs	61	35.05
2420	Hospital at Hands	28	22.84	34 34
2423	Minimal Triangulations of Graphs	28	34.55
2485	Phone Lines	19	14.47
2511	Magic Program IV	27	17.99
2631	Chomp	111	45.76
2643	Starcraft I	54	21.39
2658	Art of War	17	17.52
2661	Illumination	8	3.93
2662	Put a Point in a Hyperspace	17	9.56
2709	Untitled Problem	27	15.83
2733	K Equal Digits	12	12.30
2734	Large party	36	24.62
2735	Simplify the Railroad System	59	36.73	17 1
2855	Forest	57	11.89
2877	Another understanding of Super Dice Game	64	9.97
2879	The Cow Doctor	141	32.96	17
2880	Wild West	100	42.20	17 34
2898	Party of Cloaked Killers	28	19.38
2899	Volunteers	55	46.34	17 34
2902	Candy IV	32	48.91	50 34
2903	Transportation	11	30.95
2940	Untitled Problem II	125	15.39	34
2944	Emmons	7	7.95
2962	Painting Blocks (Act I)	108	55.83
3002	Electrophoretic	12	20.97
3005	Subdividing a Land	28	34.31
3009	Revenge of Voronoi	14	31.65
3010	Castle Wall	24	20.97
3078	Copying DNA	43	19.62
3108	Charlesbert and Merangelou	72	44.50
3166	Permutation Exponentiation	33	14.72
3197	Tree Construction	64	20.10
3208	Yet Another Longest Palindrome Problem	69	13.75
3251	Slink	15	44.44	1 1
3254	Guard	14	45.45
3305	Roman Patrollers	47	57.26
3306	Very Special Boxes	113	31.88	9 26
3309	Bulletin Board	20	21.43
3314	Umnozak	112	29.81	42 17
3347	Cestarine	61	31.23
3359	Stack	45	15.50