Compilare: main.cpp: In function 'void solve()': main.cpp:20:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | for(int j=0;j<s.size();++j) | ~^~~~~~~~~ main.cpp: At global scope: main.cpp:46:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] 46 | main() | ^~~~