二叉树的中序遍历

容易 二叉树的中序遍历

{1,#,2,3}

1
\
2
/
3

[1,3,2]

/**
* Definition of TreeNode:
* class TreeNode {
* public:
*     int val;
*     TreeNode *left, *right;
*     TreeNode(int val) {
*         this->val = val;
*         this->left = this->right = NULL;
*     }
* }
*/
class Solution {
/**
* @param root: The root of binary tree.
* @return: Inorder in vector which contains node values.
*/
vector<int> ret;
stack<TreeNode *> tmp;
public:
vector<int> inorderTraversal(TreeNode *root) {
// write your code here
//tmp.clear();
TreeNode *s = root;
while(!tmp.empty() || s){
while(s){
tmp.push(s);
s = s->left;
}
ret.push_back(tmp.top()->val);
s = tmp.top()->right;
tmp.pop();
}
return ret;
}

};