Compilare: main.cpp: In function 'int main()': main.cpp:26:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 26 | for(i=0;i<a[k].size();i++) | ~^~~~~~~~~~~~ main.cpp:42:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 42 | for(i=0;i<a[k].size();i++) | ~^~~~~~~~~~~~