【leetcode】Binary Tree Inorder Traversal

与前面的先序遍历相似。

此题为后序遍历。

 

C++：

/**
 * 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) {
        vector<int>path;
        stack<TreeNode*>stk;
        while(root!=NULL||!stk.empty())
        {
            while(root!=NULL)
            {
                stk.push(root);
                root=root->left;
            }
            if(!stk.empty())
            {
                root=stk.top();
                path.push_back(root->val);
                stk.pop();
                root=root->right;
            }
        }
        return path;
    }
};

 

Python：

# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param root, a tree node
    # @return a list of integers
    def inorderTraversal(self, root):
        if root is None:
            return []
        return self.inorderTraversal(root.left)+[root.val]+self.inorderTraversal(root.right)