Compilare: main.cpp: In function 'void add_dfs(noduri*, std::string, int)': main.cpp:24:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 24 | if(i == s.size()) { | ~~^~~~~~~~~~~ main.cpp: In function 'bool del_dfs(noduri*, std::string, int)': main.cpp:36:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | if(i == s.size()) { | ~~^~~~~~~~~~~ main.cpp: In function 'int ap_dfs(noduri*, std::string, int)': main.cpp:56:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 56 | if(i == s.size()) | ~~^~~~~~~~~~~ main.cpp: In function 'void pref_dfs(noduri*, std::string, int)': main.cpp:64:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 64 | if(i == s.size()) | ~~^~~~~~~~~~~