Compilare: user.cpp: In constructor ‘TrieNode::TrieNode()’: user.cpp:21:44: warning: passing NULL to non-pointer argument 2 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset( sons, NULL, sizeof( sons ) ); ^ user.cpp: In member function ‘void Trie::insert(TrieNode*&, const string&, int)’: user.cpp:33:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == str.size() ) ^ user.cpp: In member function ‘int Trie::find(TrieNode*, const string&, int)’: user.cpp:51:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == str.size() ) ^ user.cpp: In member function ‘bool Trie::erase(TrieNode*&, const string&, int)’: user.cpp:66:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == str.size() ) ^ user.cpp: In member function ‘int Trie::longest_common_prefix(TrieNode*, const string&, int)’: user.cpp:90:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == str.size() ) ^