LeetCode | 94. Binary Tree Inorder Traversal

 

題目：

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

Example:

Input: [1,null,2,3]
   1
    \
     2
    /
   3

Output: [1,3,2]

 

代碼：

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