zoukankan      html  css  js  c++  java
  • POJ Code the Tree 树的pufer编号

    Code the Tree
    Time Limit: 1000MS   Memory Limit: 65536K
    Total Submissions: 2259   Accepted: 859

    Description

    A tree (i.e. a connected graph without cycles) with vertices numbered by the integers 1, 2, ..., n is given. The "Prufer" code of such a tree is built as follows: the leaf (a vertex that is incident to only one edge) with the minimal number is taken. This leaf, together with its incident edge is removed from the graph, while the number of the vertex that was adjacent to the leaf is written down. In the obtained graph, this procedure is repeated, until there is only one vertex left (which, by the way, always has number n). The written down sequence of n-1 numbers is called the Prufer code of the tree.
    Your task is, given a tree, to compute its Prufer code. The tree is denoted by a word of the language specified by the following grammar:

    T ::= "(" N S ")"
    S ::= " " T S
    | empty
    N ::= number

    That is, trees have parentheses around them, and a number denoting the identifier of the root vertex, followed by arbitrarily many (maybe none) subtrees separated by a single space character. As an example, take a look at the tree in the figure below which is denoted in the first line of the sample input. To generate further sample input, you may use your solution to Problem 2568.
    Note that, according to the definition given above, the root of a tree may be a leaf as well. It is only for the ease of denotation that we designate some vertex to be the root. Usually, what we are dealing here with is called an "unrooted tree".

    Input

    The input contains several test cases. Each test case specifies a tree as described above on one line of the input file. Input is terminated by EOF. You may assume that 1<=n<=50.

    Output

    For each test case generate a single line containing the Prufer code of the specified tree. Separate numbers by a single space. Do not print any spaces at the end of the line.

    Sample Input

    (2 (6 (7)) (3) (5 (1) (4)) (8))
    (1 (2 (3)))
    (6 (1 (4)) (2 (3) (5)))
    

    Sample Output

    5 2 5 2 6 2 8
    2 3
    2 1 6 2 6
    

    Source

     
    应该是水题,所以连边表都没开,那set乱搞,然后就Wa了一个小时。
    注意整行读入的格式:cin.getline(str,MAXL,' ')
    priority_queue的比较函数自定义:priority_queue<int,vector<int>,cmp_c> q;
    还有就是普通数组储存的序列输出,在序列为空时要特判。
    by mhy12345(http://www.cnblogs.com/mhy12345/) 未经允许请勿转载

    本博客已停用,新博客地址:http://mhy12345.xyz

  • 相关阅读:
    python字符串的常用方法
    python基础之数据类型
    python自定义带参数和不带参数的装饰器
    python中logging结合pytest打印日志
    本地的项目上传到gitee仓库步骤--适合小白上手
    Python中的分数运算
    2018年6月23日开通我的Python学习博客
    python多版本兼容性问题:当同时安装Python2和Python3后,如何兼容并切换
    github之关联远程仓库
    SHH验证
  • 原文地址:https://www.cnblogs.com/mhy12345/p/3861358.html
Copyright © 2011-2022 走看看