[LeetCode OJ]Binary Tree Preorder Traversal

Given a binary tree, return the preorder traversal of its nodes' values.

For example:

Given binary tree {1,#,2,3},
   1
    \
     2
    /

   3

return [1,2,3].

先序遍历，把中序的稍

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    void inorder(TreeNode *root, vector<int> &v) {        if(root == NULL)            return;                    v.push_back(root->val);        inorder(root->left,v);        inorder(root->right,v);    }        vector<int> preorderTraversal(TreeNode *root) {        vector<int> v;        inorder(root, v);        return v;    }};

微改一下。