lintcode 68 二叉树的后序遍历

1.给出一棵二叉树，返回其节点值的后序遍历。

2.同前面两个

3./**
 * 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: Postorder in vector which contains node values.
     */
public:
    std::vector<int> binary;
    vector<int> postorderTraversal(TreeNode *root) {
        // write your code here
        if(root==NULL)return binary;
        else
        {
            postorderTraversal(root->left);
            postorderTraversal(root->right);
            binary.push_back(root->val);
            return binary;
        }
    }
};

4.和前面两个差不多.运用了递归，注意根节点的访问顺序.