Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:24:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<lv[k].size();++j) ^ user.cpp: In function ‘int main()’: user.cpp:43:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:47:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&x,&y); ^