poj 1470 Closest Common Ancestors 离线算法Tarjan求LCA

最新推荐文章于 2019-10-28 11:28:51 发布

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最新推荐文章于 2019-10-28 11:28:51 发布 · 610 阅读

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#算法 #input #tree #struct #output #pair

该博客介绍了如何使用Tarjan算法解决POJ 1470问题，涉及树结构、离线算法和最近公共祖先（LCA）的计算。通过输入、输出示例详细阐述了算法的应用过程。

Description

Write a program that takes as input a rooted tree and a list of pairs of vertices. For each pair (u,v) the program determines the closest common ancestor of u and v in the tree. The closest common ancestor of two nodes u and v is the node w that is an ancestor of both u and v and has the greatest depth in the tree. A node can be its own ancestor (for example in Figure 1 the ancestors of node 2 are 2 and 5)

Input

The data set, which is read from a the std input, starts with the tree description, in the form:

nr_of_vertices
vertex:(nr_of_successors) successor1 successor2 ... successorn
...
where vertices are represented as integers from 1 to n ( n <= 900 ). The tree description is followed by a list of pairs of vertices, in the form:
nr_of_pairs
(u v) (x y) ...

The input file contents several data sets (at least one).
Note that white-spaces