LeetCode145. 二叉树的后序遍历

 1 class Solution {
 2 public:
 3     void dfs(TreeNode* root,vector<int>&res){
 4         if(root == NULL) return;
 5 
 6         dfs(root->left,res);
 7         dfs(root->right,res);
 8         res.push_back(root->val);//对根的处理
 9     }
10     vector<int> postorderTraversal(TreeNode* root) {
11         vector<int>res;
12         dfs(root,res);
13         return res;
14     }
15 };