int sum(int x){ int ans=0; for(x;x>0;x-=lowbit(x)) ans+=a[x]; return ans; } cout<<sum(y)-sum(x-1)<<endl;
for(y;y>0;y-=lowbit(y)) ans+=a[y]; for(x-1;x>0;x-=lowbit(x)) ans-=a[x]; cout<<ans<<endl;