leetle

34. Binary Tree Inorder Traversal

Write a function solve that returns the inorder traversal of a binary tree's nodes' values. The tree is represented as an array of nodes in level-order traversal. None indicates empty nodes.

Example: Input: [1,None,2,3] Output: [1,3,2]

Make sure you return your solution, don't print!

# Binary Tree Definition
class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def solve(root):
    pass