Compilare: user.c: In function ‘main’: user.c:5:22: warning: integer overflow in expression [-Woverflow] long long p[3998],l=-(1LL<<63); ^ user.c:6:12: 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("%hd",&n); ^ user.c:6:46: 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("%hd",&n); ^ user.c:6:80: 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("%hd",&n); ^ user.c:9:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x),p[i+j]+=x,p[2*n-1+i>j?(n-1+i-j):(j-i)]+=x; ^