Compilare: user.c: In function ‘main’: user.c:9:11: warning: integer overflow in expression [-Woverflow] for(x=-(1LL<<63),i=0;i<4*n-2;i++) ^ user.c:5:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("diagonale.in","r",stdin),freopen("diagonale.out","w",stdout),scanf("%d",&n); ^ user.c:5:46: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("diagonale.in","r",stdin),freopen("diagonale.out","w",stdout),scanf("%d",&n); ^ user.c:5:80: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("diagonale.in","r",stdin),freopen("diagonale.out","w",stdout),scanf("%d",&n); ^ user.c:8:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&x),p[i+j]+=x,p[i>j?(3*n-2+i-j):(2*n-1+j-i)]+=x; ^