IT公司100题-16-层遍历二元树

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