Compilare: main.cpp: In function 'void inv(std::vector<long long int>&)': main.cpp:81:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 81 | for(int i=0; i<a.size(); i++) { | ~^~~~~~~~~ main.cpp:84:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 84 | for(int i=0; i<a.size(); i++) { | ~^~~~~~~~~