Eroare de compilare: /tmp/ccv1IWCq.o: In function `calc()': user.cpp:(.text+0x23e): undefined reference to `std::tr1::hash<std::pair<int, int> >::operator()(std::pair<int, int>) const' user.cpp:(.text+0x3e2): undefined reference to `std::tr1::hash<std::pair<int, int> >::operator()(std::pair<int, int>) const' /tmp/ccv1IWCq.o: In function `std::tr1::_Hashtable<std::pair<int, int>, std::pair<int, int>, std::allocator<std::pair<int, int> >, std::_Identity<std::pair<int, int> >, std::equal_to<std::pair<int, int> >, std::tr1::hash<std::pair<int, int> >, std::tr1::__detail::_Mod_range_hashing, std::tr1::__detail::_Default_ranged_hash, std::tr1::__detail::_Prime_rehash_policy, false, true, true>::_M_rehash(unsigned int)': user.cpp:(.text._ZNSt3tr110_HashtableISt4pairIiiES2_SaIS2_ESt9_IdentityIS2_ESt8equal_toIS2_ENS_4hashIS2_EENS_8__detail18_Mod_range_hashingENSA_20_Default_ranged_hashENSA_20_Prime_rehash_policyELb0ELb1ELb1EE9_M_rehashEj[_ZNSt3tr110_HashtableISt4pairIiiES2_SaIS2_ESt9_IdentityIS2_ESt8equal_toIS2_ENS_4hashIS2_EENS_8__detail18_Mod_range_hashingENSA_20_Default_ranged_hashENSA_20_Prime_rehash_policyELb0ELb1ELb1EE9_M_rehashEj]+0x5d): undefined reference to `std::tr1::hash<std::pair<int, int> >::operator()(std::pair<int, int>) const' collect2: error: ld returned 1 exit status