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]
递归
/**
* 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:
vector<int> inorderTraversal(TreeNode* root) {
vector<int> res;
inorder(root, res);
return res;
}
void inorder(TreeNode *root, vector<int> &res){
if(!root) return;
if(root->left) inorder(root->left, res);
res.push_back(root->val);
if(root->right) inorder(root->right, res);
}
};
