Binary Tree Inorder Traversal

Iterative Solution

Previous Attempt: Binary Tree Inorder Traversal 2023-02-06 09.33.04.excalidraw

Recursive Solution

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def inorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
        if not root:
            return []
        
        res = []
        def r(node):
            if node.left:
                r(node.left)
            
            res.append(node.val)
 
            if node.right:
                r(node.right)
        
        r(root)
 
        return res

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References

Morris Traversal

https://leetcode.com/problems/binary-tree-inorder-traversal/