Compilare: user.cpp: In function ‘int bfs(int)’: user.cpp:23:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<graph[element].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:57:15: warning: variable ‘last’ set but not used [-Wunused-but-set-variable] int first,last; ^ user.cpp: In function ‘int bfs(int)’: user.cpp:17:6: warning: ‘element’ may be used uninitialized in this function [-Wmaybe-uninitialized] int element,i; ^