Compilare: main.cpp: In function 'int main()': main.cpp:62:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 62 | for(int j = 0;j < v[a].size(); ++j) | ~~^~~~~~~~~~~~~ main.cpp:72:33: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 72 | for(int j = 0;j < v[b].size(); ++j) | ~~^~~~~~~~~~~~~