leetcode94 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?

/**
* Definition for a binary tree node.
* 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) {
vector<int> ans;
if(!root)
return ans;
stack<TreeNode*> st;
TreeNode *rt=root;//现在要考虑的节点
while(rt||!st.empty())
{
while(rt)
{
st.push(rt);
rt=rt->left;
}
TreeNode *temp=st.top();
st.pop();
ans.push_back(temp->val);
rt=temp->right;
}
return ans;
}
};

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