IT公司100题-11-求二叉树中节点的最大距离

 1 // 11.cc
 2 #include <iostream>
 3 using namespace std;
 4 
 5 typedef struct BSTreeNode {
 6     int data;
 7     BSTreeNode *left;
 8     BSTreeNode *right;
 9 } tree_node;
10 
11 // 创建二元查找树
12 void add_BSTree_node(tree_node* &p_current, int data) {
13     if (NULL == p_current) {
14         tree_node *node = new tree_node();
15         node->left = NULL;
16         node->right = NULL;
17         node->data = data;
18         p_current = node;
19     } else {
20         if (p_current->data > data)
21             add_BSTree_node(p_current->left, data);
22         else if (p_current->data < data)
23             add_BSTree_node(p_current->right, data);
24         else
25             cout << "The data has already in the tree.";
26     }
27 }
28 
29 int helper(tree_node* root, int& depth) {
30     if (!root) {
31         depth = 0;
32         return 0;
33     }
34     int ld, rd;
35     int max_left = helper(root->left, ld);
36     int max_right = helper(root->right, rd);
37     depth = max(ld, rd) + 1;
38     return max(max_left, max(max_right, ld + rd));
39 }
40 
41 // 查找最大距离
42 int max_distance(tree_node* root) {
43     int depth;
44     return helper(root, depth);
45 }
46 
47 int main() {
48     tree_node *root = NULL;
49     add_BSTree_node(root, 10);
50     add_BSTree_node(root, 2);
51     add_BSTree_node(root, 4);
52     add_BSTree_node(root, 6);
53     add_BSTree_node(root, 8);
54     add_BSTree_node(root, 12);
55     add_BSTree_node(root, 14);
56     add_BSTree_node(root, 16);
57 
58     int depth;
59     int max_d = max_distance(root);
60     cout << max_d << endl;
61 }