2.24 [4]

将两个非递减有序的链表sll1和sll2合并为一个非递增有序的链表sll3, 并且用原来sll1和sll2的空间来构造sll3

Combine 2 link-lists sll1 and sll2, which are non-decreasing, to a non-increasing sll3 by using the space of sll1 and sll2