Having done that, it goes back up and picks the second sub-list, which came from there. It's a down to base case, merges it.

就是从那里得来的,完成这些后,回到上一步。

麻省理工公开课 - 计算机科学及编程导论课程节选

PROFESSOR: OK. We can have n 4, l 3, and then, sure, we can have m sub l equal negative 2 if l equals 3 What's the second value of l that we can have?

教授：嗯，我们有ｎ４，ｌ３,然后我们有ｍｌ等于－２，如果ｌ等于３,ｌ可以有的第二个值是多少？

麻省理工公开课 - 化学原理课程节选