Compilare: main.cpp: In function 'int main()': main.cpp:14:20: warning: unused variable 'grad' [-Wunused-variable] int i,x,y,node,grad,last,elim; ^~~~ main.cpp:14:30: warning: variable 'elim' set but not used [-Wunused-but-set-variable] int i,x,y,node,grad,last,elim; ^~~~ main.cpp:52:18: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized] g << last << " " << ans; ^~~