Compilare: user.cpp: In function ‘int dfs(int)’: user.cpp:32:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a[x].size();i++) ^ user.cpp: In function ‘void read()’: user.cpp:15:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&n,&m); ^ user.cpp:19:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&x,&y); ^