Compilare: user.cpp: In function 'int main()': user.cpp:45: warning: comparison between signed and unsigned integer expressions user.cpp:48: warning: comparison between signed and unsigned integer expressions user.cpp:49: warning: comparison between signed and unsigned integer expressions user.cpp:41: warning: unused variable 'count' user.cpp: In function 'long long int backtrack(int**, int, int, std::string, std::string, long long int)': user.cpp:28: warning: control reaches end of non-void function