剑指Offer21 二叉树的层序遍历

 1 /*************************************************************************
 2     > File Name: 21_PrintTreeTopToBottom.cpp
 3     > Author: Juntaran
 4     > Mail: JuntaranMail@gmail.com
 5     > Created Time: 2016年08月30日 星期二 20时24分53秒
 6  ************************************************************************/
 7 
 8 #include <stdio.h>
 9 #include <stdlib.h>
10 #include <malloc.h>
11 #include <bits/stdc++.h>
12 
13 using namespace std;
14 
15 // 二叉树结构体
16 struct TreeNode
17 {
18     int val;
19     TreeNode* left;
20     TreeNode* right;
21 };
22 
23 // 层序遍历
24 void PrintTreeTopToBottom(TreeNode* root)
25 {
26     if (root == NULL)
27         return;
28     
29     vector<TreeNode*> vec;
30     vec.push_back(root);
31     
32     int cur = 0;
33     while (cur < vec.size())
34     {
35         printf("%d ", vec[cur]->val);
36         if (vec[cur]->left)
37             vec.push_back(vec[cur]->left);
38         if (vec[cur]->right)
39             vec.push_back(vec[cur]->right);
40         ++cur;
41     }
42     printf("
");
43 }
44 
45 TreeNode* createTree()
46 {
47     TreeNode* root = (TreeNode*)malloc(sizeof(TreeNode));
48     root->val = 8;
49     root->left = (TreeNode*)malloc(sizeof(TreeNode));
50     root->left->val = 8;
51     root->right = (TreeNode*)malloc(sizeof(TreeNode));
52     root->right->val = 7;
53     root->right->left = NULL;
54     root->right->right = NULL;
55     root->left->left = (TreeNode*)malloc(sizeof(TreeNode));
56     root->left->left->val = 9;
57     root->left->left->left = NULL;
58     root->left->left->right = NULL;
59     root->left->right = (TreeNode*)malloc(sizeof(TreeNode));
60     root->left->right->val = 2;
61     root->left->right->left = (TreeNode*)malloc(sizeof(TreeNode));
62     root->left->right->left->val = 4;
63     root->left->right->left->left = NULL;
64     root->left->right->left->right = NULL;
65     root->left->right->right = (TreeNode*)malloc(sizeof(TreeNode));
66     root->left->right->right->val = 7;
67     root->left->right->right->left = NULL;
68     root->left->right->right->right = NULL;
69     
70     return root;
71 }
72 
73 int main()
74 {
75     TreeNode* test = createTree();
76     PrintTreeTopToBottom(test);
77 }