145-Binary-Tree-Postorder-Traversal.py

'''
Given the root of a binary tree, return the postorder traversal of its nodes' values.
'''

# 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 postorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
        # One Liner
        return self.postorderTraversal(root.left) + self. postorderTraversal(root.right) + [root.val] if root else []