DFS: 94. Binary Tree Inorder Traversal

94. Binary Tree Inorder Traversal

 

# 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]:
        # inorder: dfs 에서,.. 왼쪽, 현재, 오른쪽 순회
        # dfs 니깐, stack 이나 재귀로

        if not root:
            return []

        res = []
        def dfs(node):
            if node.left:
                dfs(node.left)
            res.append(node.val)
            if node.right:
                dfs(node.right)

        dfs(root)
        return res