zoukankan      html  css  js  c++  java
  • Tree Walk Aizu

    Binary trees are defined recursively. A binary tree T is a structure defined on a finite set of nodes that either

    contains no nodes, or
    is composed of three disjoint sets of nodes:

    • a root node.
    • a binary tree called its left subtree.
    • a binary tree called its right subtree.
      Your task is to write a program which perform tree walks (systematically traverse all nodes in a tree) based on the following algorithms:

    Print the root, the left subtree and right subtree (preorder).
    Print the left subtree, the root and right subtree (inorder).
    Print the left subtree, right subtree and the root (postorder).
    Here, the given binary tree consists of n nodes and evey node has a unique ID from 0 to n-1.

    Input

    The first line of the input includes an integer n, the number of nodes of the tree.

    In the next n linen, the information of each node is given in the following format:

    id left right

    id is the node ID, left is ID of the left child and right is ID of the right child. If the node does not have the left (right) child, the left(right) is indicated by -1

    Output

    In the 1st line, print “Preorder”, and in the 2nd line print a list of node IDs obtained by the preorder tree walk.

    In the 3rd line, print “Inorder”, and in the 4th line print a list of node IDs obtained by the inorder tree walk.

    In the 5th line, print “Postorder”, and in the 6th line print a list of node IDs obtained by the postorder tree walk.

    Print a space character before each node ID.

    Constraints

    1 ≤ n ≤ 25

    Sample Input 1

    9
    0 1 4
    1 2 3
    2 -1 -1
    3 -1 -1
    4 5 8
    5 6 7
    6 -1 -1
    7 -1 -1
    8 -1 -1

    Sample Output 1

    Preorder
    0 1 2 3 4 5 6 7 8
    Inorder
    2 1 3 0 6 5 7 4 8
    Postorder
    2 3 1 6 7 5 8 4 0
    在这里插入图片描述

    Reference

    Introduction to Algorithms, Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein. The MIT Press.

    Code

    /*
                                    ^....0
                                   ^ .1 ^1^
                                   ..     01
                                  1.^     1.0
                                 ^ 1  ^    ^0.1
                                 1 ^        ^..^
                                 0.           ^ 0^
                                 .0            1 .^
                                 .1             ^0 .........001^
                                 .1               1. .111100....01^
                                 00                 11^        ^1. .1^
                                 1.^                              ^0  0^
                                   .^                                 ^0..1
                                   .1                                   1..^
                                 1 .0                                     ^  ^
                                  00.                                     ^^0.^
                                  ^ 0                                     ^^110.^
                              0   0 ^                                     ^^^10.01
                       ^^     10  1 1                                      ^^^1110.1
                       01     10  1.1                                      ^^^1111110
                       010    01  ^^                                        ^^^1111^1.^           ^^^
                       10  10^ 0^ 1                                            ^^111^^^0.1^       1....^
                        11     0                                               ^^11^^^ 0..  ....1^   ^ ^
                        1.     0^                                               ^11^^^ ^ 1 111^     ^ 0.
                       10   00 11                                               ^^^^^   1 0           1.
                       0^  ^0  ^0                                                ^^^^    0            0.
                       0^  1.0  .^                                               ^^^^    1 1          .0
                       ^.^  ^^  0^                             ^1                ^^^^     0.         ^.1
                       1 ^      11                             1.                ^^^     ^ ^        ..^
                      ^..^      ^1                             ^.^               ^^^       .0       ^.0
                      0..^      ^0                              01               ^^^       ..      0..^
                     1 ..        .1                             ^.^              ^^^       1 ^  ^0001
                    ^  1.        00                              0.             ^^^        ^.0 ^.1
                    . 0^.        ^.^                             ^.^            ^^^         ..0.0
                   1 .^^.         .^                  1001        ^^            ^^^         . 1^
                   . ^ ^.         11                0.    1         ^           ^^          0.
                    0  ^.          0              ^0       1                   ^^^          0.
                  0.^  1.          0^             0       .1                   ^^^          ..
                  .1   1.          00            .        .1                  ^^^           ..
                 1      1.         ^.           0         .^                  ^^            ..
                 0.     1.          .^          .         0                                  .
                 .1     1.          01          .        .                                 ^ 0
                ^.^     00          ^0          1.       ^                                 1 1
                .0      00           .            ^^^^^^                                   .
                .^      00           01                                                    ..
               1.       00           10                                                   1 ^
              ^.1       00           ^.                                            ^^^    .1
              ..        00            .1                                        1..01    ..
             1.1         00           1.                                       ..^      10
            ^ 1^         00           ^.1                                      0 1      1
            .1           00            00                                       ^  1   ^
             .           00            ^.^                                        10^  ^^
           1.1           00             00                                              10^
           ..^           1.             ^.                                               1.
          0 1            ^.              00                 00                            .^
            ^            ^.              ^ 1                00   ^0000^     ^               01
         1 0             ^.               00.0^              ^00000   1.00.1              11
         . 1              0               1^^0.01                      ^^^                01
          .^              ^                1   1^^                                       ^.^
        1 1                                                                              0.
        ..                                                                              1 ^
         1                                                                               1
       ^ ^                                                                             .0
       1                                                                             ^ 1
       ..                                                          1.1            ^0.0
      ^ 0                                                           1..01^^100000..0^
      1 1                                                            ^ 1 ^^1111^ ^^
      0 ^                                                             ^ 1      1000^
      .1                                                               ^.^     .   00
      ..                                                                1.1    0.   0
      1.                                                                  .    1.   .^
      1.                                                                 1    1.   ^0
     ^ .                                                                 ^.1 00    01
     ^.0                                                                  001.     .^
     */
    // Virtual_Judge —— Tree Walk Aizu - ALDS1_7_C.cpp created by VB_KoKing on 2019-05-08:20.
    /* Procedural objectives:
    
     Variables required by the program:
    
     Procedural thinking:
    
     Functions required by the program:
     
     Determination algorithm:
     
     Determining data structure:
     
    
    */
    /* My dear Max said:
    "I like you,
    So the first bunch of sunshine I saw in the morning is you,
    The first gentle breeze that passed through my ear is you,
    The first star I see is also you.
    The world I see is all your shadow."
    
    FIGHTING FOR OUR FUTURE!!!
    */
    #include <iostream>
    
    #define MAX 10007
    #define NIL -1
    
    using namespace std;
    
    struct Node {int parent, left, right;};
    struct Node T[MAX];
    int n;
    
    //前序遍历
    void pre_parse(int u) {
        if (u == NIL) return;
        cout << " " << u;
        pre_parse(T[u].left);
        pre_parse(T[u].right);
    }
    
    //中序遍历
    void in_parse(int u) {
        if (u == NIL) return;
        in_parse(T[u].left);
        cout << " " << u;
        in_parse(T[u].right);
    }
    
    //后序遍历
    void post_parse(int u) {
        if (u == NIL) return;
        post_parse(T[u].left);
        post_parse(T[u].right);
        cout << " " << u;
    }
    
    int main() {
        cin>>n;
        int v, l, r, root;
        for (int i = 0; i < n; i++)
            T[i].parent = NIL;
    
        for (int i = 0; i < n; i++) {
            cin >> v >> l >> r;
            T[v].left = l;
            T[v].right = r;
            if (l != NIL) T[l].parent = v;
            if (r != NIL) T[r].parent = v;
        }
    
        for (int i = 0; i < n; i++)
            if (T[i].parent == NIL)
                root = i;
    
        cout << "Preorder" << endl;
        pre_parse(root);
        cout << endl << "Inorder" << endl;
        in_parse(root);
        cout << endl << "Postorder" << endl;
        post_parse(root);
        cout << endl;
        return 0;
    }
    
  • 相关阅读:
    js对象数组中的某属性值 拼接成字符串
    mongodb 简单的增删改查
    celery简单使用
    Redis简单操作
    三大认证源码分析
    认证、权限、频率、自定义签发token-多方式登录
    jwt认证
    视图家族
    day75作业
    day74作业
  • 原文地址:https://www.cnblogs.com/AlexKing007/p/12338334.html
Copyright © 2011-2022 走看看