Python 树的遍历递归和循环

class TreeNode(object): def __init__(self, x): self.val = x self.left = None self.right = None ###递归的形式 先序遍历 中序遍历 后序遍历 def preOrderRecursive(root): if root == None: return None print(root.val) preOrderRecursive(root.left) preOrderRecursive(root