Compilare: user.cpp: In function ‘int main()’: user.cpp:31:8: warning: unused variable ‘f’ [-Wunused-variable] FILE *f=freopen("dfs.in","r",stdin), ^ user.cpp:32:3: warning: unused variable ‘g’ [-Wunused-variable] *g=freopen("dfs.out","w",stdout); ^ user.cpp:33:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:36:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^