leetcode-655-輸出二叉樹

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def printTree(self, root: TreeNode) -> List[List[str]]:
        depth = self.get_depth(root)
        width = 2**depth -1
        res = [["" for j in range(width)] for i in range(depth)]
        self.fill_res(root, res, 0, width, 0)

        return res

    def fill_res(self, root:TreeNode, res:List[List[str]], start:int, end:int, depth_a:int):
        if (root is None) or start > end:
            return

        mid = start + (end-start) //2 
        res[depth_a][mid] = str(root.val)
        #print(depth_a)
        self.fill_res(root.left, res, start, mid-1, depth_a+1)
        self.fill_res(root.right, res, mid+1, end, depth_a+1)
   


    def get_depth(self, root:TreeNode)-> int:

        if root is None:
            return 0

        return max(self.get_depth(root.left), self.get_depth(root.right))+1