Compilare: user.cpp: In function ‘int main()’: user.cpp:20:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[i].size(); j++) ^ user.cpp:31:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[S].size(); j++){ ^ user.cpp:45:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[current.first].size(); j++) ^