When these two merges are done, we're basically at a stage in that branch where we can now merge those two together, which gives us that, and it goes through the rest of it.

拿到从那边得到的第二个子列表，这是一个基本情况,合并它，当这两个合并完成后，我们基本到了该分支阶段，这里我们可以把两个合并在一起。

麻省理工公开课 - 计算机科学及编程导论课程节选