If you need only to compute the distance and not alignments, as is usually the case, it is easy to reduce this to o (n), since only the previous row is required to compute the next.

如果您只需要计算距离，不需要校准，就像通常情况那样，那么可以很容易地把空间需求降到O (n)，因为计算下一行只需要前面一行。

youdao

As the Citro? N accelerated southward across the city, the illuminated profile of the Eiffel Tower appeared, shooting skyward in the distance to the right.

雪铁龙继续加速向南穿越城区。这时被照亮的埃菲尔铁塔的轮廓开始显现出来。在车右边铁塔直插云霄。

youdao

N'Guessan deservedly pulled them within touching distance in the 73rd minute with a powerful header, but any hope of an unlikely point was short-lived as Olofinjana diverted Jason Koumas' goal-bound effort home.

BBC: Scunthorpe 2-4 Cardiff