二叉树遍历 前中后

旧城等待， 2022-08-18 15:27 222阅读 0赞

这里写图片描述

  1. #include <iostream>
  3. using namespace  std;
  5. struct t{
  6.     int v;
  7.     struct t * left;
  8.     struct t * right;
  10. };
  12. void preorder(struct t *tree){
  13.     if (tree == NULL){
  14.         return;
  15.     }   
  16.     cout << "i'm root " << tree->v << endl;
  17.     preorder(tree->left);
  18.     preorder(tree->right);
  19. }
  21. void backorder(struct t *tree){
  22.     if (tree == NULL){
  23.         return;
  24.     }   
  25.     backorder(tree->left);
  26.     backorder(tree->right);
  27.     cout << "i'm root " << tree->v << endl;
  28. }
  30. void midorder(struct t *tree){
  31.     if (tree == NULL){
  32.         return;
  33.     }   
  34.     midorder(tree->left);
  35.     cout << "i'm root " << tree->v << endl;
  36.     midorder(tree->right);
  37. }
  40. int main()
  41. {
  42.     struct t trees[5]={};
  43.     cout << "hello world" << endl;
  44.     trees[0].v = 1;
  45.     trees[1].v = 3;
  46.     trees[2].v = 5;
  47.     trees[3].v = 7;
  48.     trees[4].v = 9;
  51.     for (int i=0; i<5; i++){
  52.         cout << trees[i].v << endl;
  53.     }   
  55.     trees[0].left = &trees[1];
  56.     trees[0].right = &trees[2];
  58.     trees[1].left = &trees[3];
  59.     trees[1].right = &trees[4];
  61.     cout << "preorder" << endl;
  63.     preorder(trees);
  65.     cout << "backorder" << endl;
  67.     backorder(trees);
  69.     cout << "midorder" << endl;
  71.     midorder(trees);
  73.     return 0;
  75. }
  77. [root@ bigo]# g++ tree.cpp 
  78. [root@ bigo]# 
  79. [root@ bigo]# 
  80. [root@ bigo]# ./a.out 
  81. hello world
  82. 1
  83. 3
  84. 5
  85. 7
  86. 9
  87. preorder
  88. i'm root 1
  89. i'm root 3
  90. i'm root 7
  91. i'm root 9
  92. i'm root 5
  93. backorder
  94. i'm root 7
  95. i'm root 9
  96. i'm root 3
  97. i'm root 5
  98. i'm root 1
  99. midorder
  100. i'm root 7
  101. i'm root 3
  102. i'm root 9
  103. i'm root 1
  104. i'm root 5
  105. [root@ bigo]#

我去滴滴面试，没答出这道题，遗憾。

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