[LeetCode]Binary Tree Inorder Traversal
Given a binary tree, return the inorder traversal of its nodes' values.
For example:
Given binary tree {1,#,2,3}
,
1 \ 2 / 3
return [1,3,2]
.
Note: Recursive solution is trivial, could you do it iteratively?
非递归中序遍历,基础吧, s.pop() 原来是返回空的。。。
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<int> inorderTraversal(TreeNode *root) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
stack<TreeNode*> S;
vector<int> ret;
ret.clear();
if(root==NULL)
return ret;
TreeNode *p =root;
while(!S.empty()|| p)
{
if(p!=NULL)
{
S.push(p);
p= p->left;
}else{
p = S.top();
S.pop();
ret.push_back(p->val);
p = p->right;
}
}
return ret;
}
};