1 /**
2 * Definition for a binary tree node.
3 * struct TreeNode {
4 * int val;
5 * TreeNode *left;
6 * TreeNode *right;
7 * TreeNode(int x) : val(x), left(NULL), right(NULL) {}
8 * };
9 */
10 class Solution {
11 public:
12 vector<int> inorderTraversal(TreeNode* root) {
13 vector<int> res;
14 if(root == NULL)
15 return res;
16 stack<TreeNode *> node;
17 node.push(root);
18 TreeNode *p,*cur;
19 if(root->left != NULL)
20 {
21 node.push(root->left);
22 p = root->left;
23 }
24 else
25 {
26 res.push_back(root->val);
27 node.pop();
28 if(root->right != NULL)
29 {
30 node.push(root->right);
31 p = root->right;
32 }
33 else return res;
34 }
35 while(!node.empty())
36 {
37 while(p->left != NULL)
38 {
39 p = p->left;
40 node.push(p);
41 }
42 cur = node.top();
43 node.pop();
44 res.push_back(cur->val);
45 if(cur->right != NULL)
46 {
47 p = cur->right;
48 node.push(p);
49 }
50 }
51 return res;
52 }
53 };
