[leetcode] binary tree inorder traversal

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?

confused what "{1,#,2,3}" means? > read more on how binary tree is serialized on OJ.

/**
 * 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 inorderTraversal(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        stack my_stack;
        TreeNode *p = root;
        vector result;
       
        if (!p)
            return result;
           
        while (p)
        {
            my_stack.push(p);
            p = p->left;
        }
       
        while (!my_stack.empty())
        {  
            TreeNode *top = my_stack.top();
            my_stack.pop();
            result.push_back(top->val);

            p = top->right;
           
            while (p)
            {
                my_stack.push(p);
                p = p->left;
            }
        }
       
        return result;
    }
};