The rivalry between the two aeronautics giants also took a new turn on Tuesday when Boeing accused Airbus of violating world trade regulations by seeking European government financing for its new A350 planes.

VOA: standard.2009.06.16

Down here, I've just got two things to merge, and then I've got things of size two to merge and then things of size four to merge. But notice a trade off. I have n operations if you like down there of size one.

但是n的大小是不同的，是吗？在这里我们只要合并两个元素,然后是合并长度为2的列表,接下来是合并长度为4的列表,但是观察一下之间的权衡关系。

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