IT公司100题-11-求二叉树中节点的最大距离
问题描述：
写程序，求一棵二叉树中相距最远的两个节点之间的距离。
10
/ \
6 14
/ \ / \
4 8 12 16
/ \
6 14
/ \ / \
4 8 12 16
分析：
二叉树中最远的两个节点，要么是根和一个叶子节点，要么是两个叶子节点。
代码实现：
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 }
