Compilare: user.cpp: In function ‘std::__cxx11::string str(int, bool, bool)’: user.cpp:20:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(ignore1) ^ user.cpp: In function ‘int main()’: user.cpp:61:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<R.size();i++) ~^~~~~~~~~ user.cpp:69:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(K>R.size()) {g<<-1; return 0;} ~^~~~~~~~~