【leetcode刷题】T111-二叉树的中序遍历

示例:

输入: [,null,,]
   
    \
     
    /
   

输出: [,,]

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def inorderTraversal(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        num = []
        self.traversal(root, num)
        return num
    
    def traversal(self, node, num):
        if node:
            self.traversal(node.left, num)
            num.append(node.val)
            self.traversal(node.right, num)

/**
 * 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> num;
        Solution().traversal(root, num);
        return num;
    }
    
    void traversal(TreeNode* node, vector<int>& num){
        if(node){
            traversal(node->left, num);
            num.push_back(node->val);
            traversal(node->right, num);
        }
    }
};