Compilare: main.cpp: In function 'bool fold(std::__cxx11::string)': main.cpp:16:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++){ ~^~~~~~~~~ main.cpp: In function 'std::__cxx11::string find_cuv(int)': main.cpp:25:9: warning: variable 'ok' set but not used [-Wunused-but-set-variable] int ok; ^~ main.cpp: In function 'int main()': main.cpp:97:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<graf[i].size();j++){ ~^~~~~~~~~~~~~~~ main.cpp:85:9: warning: unused variable 'dummy' [-Wunused-variable] int dummy=0; ^~~~~