Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
2273	Ferries	32	18.79
2275	Toil for Oil	14	30.41
2318	Overlapping Words	89	22.26
2319	Sequence	218	28.10
2323	Broken Compass	46	13.66
2325	String Distance	213	21.47
2413	Building Beacons	42	20.83
2417	Eliminate The Enemies	22	19.74
2418	Flying Frogs	61	35.05
2420	Hospital at Hands	30	23.08	34 34
2423	Minimal Triangulations of Graphs	29	34.94
2485	Phone Lines	19	14.38
2511	Magic Program IV	27	17.99
2631	Chomp	111	45.76
2643	Starcraft I	56	21.62
2658	Art of War	17	16.11
2661	Illumination	8	3.93
2662	Put a Point in a Hyperspace	18	9.65
2709	Untitled Problem	29	16.35
2733	K Equal Digits	15	13.38
2734	Large party	37	25.13
2735	Simplify the Railroad System	61	36.06	17 1
2855	Forest	59	12.37
2877	Another understanding of Super Dice Game	66	10.25
2879	The Cow Doctor	144	33.33	17
2880	Wild West	100	42.25	17 34
2898	Party of Cloaked Killers	28	17.42
2899	Volunteers	58	46.69	17 34
2902	Candy IV	32	48.91	50 34
2903	Transportation	11	24.07
2940	Untitled Problem II	125	15.39	34
2944	Emmons	7	7.41
2962	Painting Blocks (Act I)	108	57.38
3002	Electrophoretic	14	20.00
3005	Subdividing a Land	28	33.02
3009	Revenge of Voronoi	14	30.80
3010	Castle Wall	25	19.85
3078	Copying DNA	45	19.85
3108	Charlesbert and Merangelou	72	44.50
3166	Permutation Exponentiation	34	14.92
3197	Tree Construction	64	20.10
3208	Yet Another Longest Palindrome Problem	68	13.77
3251	Slink	15	34.04	1 1
3254	Guard	15	44.44
3305	Roman Patrollers	50	58.82
3306	Very Special Boxes	112	31.51	9 26
3309	Bulletin Board	23	21.53
3314	Umnozak	113	29.75	42 17
3347	Cestarine	61	28.97
3359	Stack	47	15.73