094_二叉树的中序遍历

简单

Java

class Solution {
    public List<Integer> inorderTraversal(TreeNode root) {
        ArrayList<Integer> res = new ArrayList<>();
        if(root == null){
            return res;
        }
        inorder(root,res);
        return res;

    }
    public void inorder(TreeNode root,ArrayList<Integer> res){
        if(root.left != null) {
            inorder(root.left, res);
        }
        res.add(root.val);
        if(root.right != null){
            inorder(root.right,res);
        }
    }
}

Python

class Solution:
    def inorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
        res = []
        def getRes(node):                   
            if not node: return
            if node.left: getRes(node.left)           
            res.append(node.val)            
            if node.right: getRes(node.right)
        getRes(root)                       
        return res