UVa 11173
UVa 11236
IVa 12532
UVa 775
UVa 1262
UVa 299
UVa 543
UVa 374
UVA 12318
AC in UVa, WA in Mooshak
UVa 11195
UVa 441
UVa 11565
UVa 12346
UVa 12455
fixed wrong limit
Optimized using bidirectional search and enabled for n<=30 and each number <=1000000000
(Supposed) speedup with bitset