Compilare: main.cpp: In function 'int main()': main.cpp:58:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 58 | for (i = 0; i < sol.size(); i++, cout << "\n") | ~~^~~~~~~~~~~~ main.cpp:59:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 59 | for (int j = 0; j < sol[i].size(); j++) | ~~^~~~~~~~~~~~~~~