Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:19:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<gr[t].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:84:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<gr[xf].size(); i++) ^ user.cpp:103:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(t=0; t<gr[a].size(); t++) ^