Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
1701	Earth Observation with a Mobile Robot Team	9	37.04
1704	Countdown	298	25.14	26 9
1705	The Game of Efil	89	49.61
1708	Square Count	71	30.72
1709	Swamp Things	287	40.34
1715	Another Necklace Problem	50	19.00
1722	Life, the Universe, and Everything II	66	33.90
1725	The Importance	96	40.89
1726	Exchange	18	6.52
1739	Yet Another Equation	226	40.95
1772	Find The Determinant II	87	29.55
1788	Fractan	44	32.76
1793	Text Generater II	55	30.43
1800	Fixed Partition Contest Management	59	36.25
1803	Fold	57	41.94
1810	Nuclear Plants	21	13.83
1815	Problems Collection (Volume X)	76	7.33
1838	Ticket to Ride	85	40.98
1842	Lineland Airport	33	19.10
1865	Making Waves	186	43.28	26 9
1877	Enrich my purse	152	27.14
1880	Hanoi Calls	202	55.04
1962	Circles	58	19.63
1963	Image Projections	104	32.61
1964	Tree cut	147	37.84
1966	Ski Valley	113	18.41
2002	Random Number Generator	97	42.09
2019	The Rolling Ball	3	5.26
2022	Truth Or Lie	102	22.42
2023	One Instruction Computer Simulator	47	11.04	42 42
2031	Please help You-Know-Who	36	33.33
2052	Hexagonal Parcels	75	29.07
2060	Tough Water Level	34	26.34
2070	Minimum Distance	82	16.94	17 1
2129	Cake	70	21.63
2130	Trolls	29	46.03
2132	Puzzle	85	32.11
2140	(un)Fair Play	74	38.68
2141	Golden Garden	17	17.70
2142	Arranging Flowers	23	9.57
2144	K Edge-disjoint Branchings	9	16.14
2147	Root of a Linear Equation	59	8.47	34 17
2151	Digital Calculator	22	5.80
2153	Internet is Faulty	64	41.34
2154	Kruskal	83	14.64
2159	Delicious Cake	29	15.94
2160	Here-There	28	26.18
2161	Pixel Shuffle	29	19.57	50 17
2162	Towers of Powers	28	19.72
2180	Justice League	76	48.04