Compilare: main.cpp: In function 'int main()': main.cpp:59:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 59 | for(int i=0; i<solution.size(); i++){ | ~^~~~~~~~~~~~~~~~ main.cpp:61:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | for(int j=0; j<solution[i].size(); j++) | ~^~~~~~~~~~~~~~~~~~~