Compilare: user.cpp: In function ‘void euler(int, int)’: user.cpp:23:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[x].size();i++) ~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:46:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<eu.size();i++) ~^~~~~~~~~~