Compilare: user.cpp: In function ‘void add(int, int)’: user.cpp:38:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < graph[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:86:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < gv.size(); ++i){ ^ user.cpp:90:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i; j < gv.size(); ++j){ ^