/**递归的写法
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
void MiddleTravel(TreeNode * root,vector<int>&result_vec) {
if(root!=NULL) {
MiddleTravel(root->left,result_vec);
result_vec.push_back(root->val);
MiddleTravel(root->right,result_vec);
}
}
class Solution {
public:
vector<int> inorderTraversal(TreeNode* root) {
vector<int>result_vec;
MiddleTravel(root,result_vec);
return result_vec;
}
};
下面是一个不用递归的写法，用栈：
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>result_vec;
14 stack<TreeNode *>q_stack;
15 TreeNode *NowNode=root;
16 while(NowNode||!q_stack.empty()) {
17 if(NowNode!=NULL) {
18 q_stack.push(NowNode);
19 NowNode=NowNode->left;
20 }
21 else {
22 NowNode=q_stack.top();
23 result_vec.push_back(NowNode->val);
24 q_stack.pop();
25 NowNode=NowNode->right;
26 }
27 }
28 return result_vec;
29 }
30 };