Compilare: user.cpp: In function ‘void euler(int)’: user.cpp:19:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[x].size(); ++i) ^ user.cpp:25:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[aux].size(); ++j) ^ user.cpp: In function ‘int main()’: user.cpp:45:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol.size(); ++i) ^