Compilare: main.cpp: In function 'void add(Node&, const string&)': main.cpp:34:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 34 | for (int p = 0; p < s.size(); p++) { | ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:116:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 116 | for (int i = 0; i < s.size(); i++) { | ~~^~~~~~~~~~ main.cpp:143:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 143 | for (int j = 0; j < words[i].size(); j++) { | ~~^~~~~~~~~~~~~~~~~