589. N 叉树的前序遍历
Ideas二叉树的前序遍历模板，拿过来稍微一改就完事了。
def preorderTraversalLoop(node): if not node: return stack = [node] # list 模拟 stack while stack: tmp = stack.pop() print(tmp.value, end=' ') if tmp.right: stack.append(tmp.right) if tmp.left: stack.append(tmp.left)Code Python
from typing import List # Definition for a Node. class Node: def __init__(self, val=None, children=None): self.val = val
self.children = children class Solution: def preorder(self, root: 'Node') -> List[int]: if not root: return [] stack, ans = [root], [] while stack: item = stack.pop() ans.append(item.val) for i in range(len(item.children) - 1, -1, -1): stack.append(item.children[i]) return ans
