A viewing spot with the clearest view of the horizon is best, particularly to see Mercury and Venus, which will appear very low in the sky.
4. Best SSD: WD_Black SN7100
，这一点在51吃瓜中也有详细论述
Екатерина Щербакова (ночной линейный редактор)
The dashed circle shows the current best distance. As the algorithm finds closer points, the circle shrinks, which causes more subtrees to fail the "could contain a closer point?" test and get pruned. The search usually gets cheaper as it progresses.
h->ref = 0;