poj1240 Pre-Post-erous!

最新推荐文章于 2020-07-02 23:13:01 发布

原创

最新推荐文章于 2020-07-02 23:13:01 发布 · 2.8k 阅读

3 ·

CC 4.0 BY-SA版权

文章标签：

#poj1240 #树 #先根遍历 #后根遍历 #递归

该博客讨论了在给定先根遍历和后根遍历的情况下，如何确定m叉树的可能性。举例说明了在不同情况下，可能存在多个不同的树结构，这些树具有相同的先序和后序遍历。文章还提到了深度优先搜索（DFS）中的先根遍历和后根遍历的概念，并指出在这种情况下，无法仅凭先序和后序遍历来确定唯一的中序遍历。

照例先上题目：

1:Pre-Post-erous!
查看提交统计提问
总时间限制: 1000ms 内存限制: 65536kB
描述
We are all familiar with pre-order, in-order and post-order traversals of binary trees. A common problem in data structure classes is to find the pre-order traversal of a binary tree when given the in-order and post-order traversals. Alternatively, you can find the post-order traversal when given the in-order and pre-order. However, in general you cannot determine the in-order traversal of a tree when given its pre-order and post-order traversals. Consider the four binary trees below:

a a a a
/ / \ \
b b b b
/ \ / \
c c c c

All of these trees have the same pre-order and post-order traversals. This phenomenon is not restricted to binary trees, but holds