Compilare: main.cpp: In function 'bool solve(long long int)': main.cpp:56:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 56 | for(i=0; i<nr.size(); i++) | ~^~~~~~~~~~ main.cpp:57:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 57 | for(j=0; j<nr.size(); j++) | ~^~~~~~~~~~