Compilare: main.cpp: In function 'void insert(TrieNode*, std::string)': main.cpp:32:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 32 | for (int i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'int getNumberOfApparitions(TrieNode*, std::string)': main.cpp:49:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | for (int i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'void deleteNode(TrieNode*, std::string)': main.cpp:71:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 71 | for (int i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'int getLongestPrefix(TrieNode*, std::string)': main.cpp:89:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 89 | for(i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~