Compilare: main.cpp: In function 'int main()': main.cpp:58:42: 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(int j = 2; j < vec.size(); ++j) | ~~^~~~~~~~~~~~ main.cpp:71:42: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 71 | for(int j = 2; j < vec.size(); ++j) | ~~^~~~~~~~~~~~