Compilare: user.cpp: In function 'int is_k_alike(int)': user.cpp:17: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void put_trie(int, std::string, int, int)': user.cpp:32: warning: comparison between signed and unsigned integer expressions user.cpp:38: warning: unused variable 'ch' user.cpp: In function 'int main()': user.cpp:56: warning: format '%s' expects type 'char*', but argument 3 has type 'char (*)[3000]' user.cpp:59: warning: comparison between signed and unsigned integer expressions user.cpp:78: warning: comparison between signed and unsigned integer expressions