题解 | 二叉树的前序遍历
二叉树的前序遍历
https://www.nowcoder.com/practice/5e2135f4d2b14eb8a5b06fab4c938635
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
#
# @param root TreeNode类
# @return int整型一维数组
#
class Solution:
def preorderTraversal(self , root: TreeNode) -> List[int]:
# write code here
result = []
def traverse(node):
if not node:
return
result.append(node.val)
traverse(node.left)
traverse(node.right)
traverse(root)
return result
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