【20240926每日一题】树的先序遍历

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1

难度

中

题目

请用熟悉的编程语言实现树的先序遍历

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3
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class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

    def preorderTraversal(root):
        result = []

        if root is None:
            return result

        result.append(root.val)
        result += TreeNode.preorderTraversal(root.left)
        result += TreeNode.preorderTraversal(root.right)
        return  result

if __name__ == '__main__':
    root = TreeNode(1)
    root.left = TreeNode(2, TreeNode(4), TreeNode(5))
    root.right = TreeNode(3)

    print(TreeNode.preorderTraversal(root))