Compilare: main.cpp: In function 'void add_dfs(noduri*, std::string&, int)': main.cpp:22:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 22 | if(pos == s.size()) { | ~~~~^~~~~~~~~~~ main.cpp: In function 'bool del_dfs(noduri*, std::string&, int)': main.cpp:33:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 33 | if(pos == s.size()) { | ~~~~^~~~~~~~~~~ main.cpp: In function 'int ap_dfs(noduri*, std::string&, int)': main.cpp:54:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 54 | if(pos == s.size()) | ~~~~^~~~~~~~~~~ main.cpp: In function 'void pref_dfs(noduri*, std::string&, int)': main.cpp:62:46: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 62 | if(start->v[s[pos] - 'a'] == NULL || pos == s.size()) | ~~~~^~~~~~~~~~~