Sphere Online Judge (SPOJ)

list of classical problems

ID	NAME	USERS	ACC %	DIFFICULTY C I
3941	Kth Shortest Path	26	29.38
3942	Cleaning Robot	32	64.29
3961	Journey with Pigs	130	41.30
3965	Minimax Triangulation	58	34.60
3970	Convert to Decimal Base System	53	38.60	17 17
3972	Stargates	45	13.29
3981	Shortest Regular Bracket	80	35.98
4003	Subway planning	40	17.94
4004	Exploding CPU	141	46.17
4008	Con Voi	9	56.00
4010	Chặt cây	8	36.00
4021	Bipalindrome	183	30.81
4034	Pizza Delivery	52	16.59
4052	Game	75	30.28
4060	A game with probability	200	21.88
4062	Rob Mini-Safe	112	39.35
4069	Morphing is Fun	29	20.57
4070	Two Professors	101	14.28
4083	Tele Broadcast	67	50.52
4097	Locomotive	34	43.21
4142	Ellipse	17	8.46
4154	IZBORI	36	24.54
4156	PLAHTE	65	36.36
4160	A1 Road	87	50.68
4178	Distance on a square lattice	121	53.50
4185	Cube	52	35.93
4188	Amazing equality	38	13.58
4189	Landing	4	3.64
4202	Brackets Parade	232	44.26
4210	Fast Maximum Matching	13	48.57
4211	Fast Maximum Flow	16	21.67
4212	Another Longest Increasing Subsequence Problem	11	46.43
4225	Payment System	29	66.07
4275	rotate it	40	55.70
4278	Battlefield	6	46.15
4307	Stamps	28	40.24
4308	Byteantean towns	55	24.22
4309	Circular game	32	19.89
4311	Quasi-template	59	34.17
4324	The fate of the pineapple	40	28.41
4361	Connected Points	9	52.17
4378	Twofive	63	31.96
4407	Counting Arborescence	100	34.02
4410	Repair the Door	58	22.49
4411	Counting Expressions	29	41.89
4414	Highway	53	21.89
4420	Counting Graphs	67	36.36
4421	Irreducible polynomials over GF2	62	17.88
4453	Bouncing Balls II	221	27.59
4455	Going to the Movies	86	36.33