Compilare: main.cpp: In member function 'void TrieNode::insert(std::__cxx11::string&, int)': main.cpp:19:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ind == s.size()) { ~~~~^~~~~~~~~~~ main.cpp: In member function 'void TrieNode::del(std::__cxx11::string&, int)': main.cpp:28:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ind == s.size()) { ~~~~^~~~~~~~~~~ main.cpp: In member function 'int TrieNode::count(std::__cxx11::string&, int)': main.cpp:35:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ind == s.size()) { ~~~~^~~~~~~~~~~ main.cpp: In member function 'int TrieNode::lp(std::__cxx11::string&, int)': main.cpp:43:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ind == s.size() || !children[s[ind]-'a']) { ~~~~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:53:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in","r",stdin); ^ main.cpp:54:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out","w",stdout); ^